A telescope is an optical instrument that makes distant objects appear magnified by using an arrangement of lenses or curved mirrors and lenses, or various devices used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation. The first known practical telescopes were refracting telescopes invented in the Netherlands at the beginning of the 17th century, by using glass lenses, they were used for both terrestrial applications and astronomy. The reflecting telescope, which uses mirrors to collect and focus light, was invented within a few decades of the first refracting telescope. In the 20th century, many new types of telescopes were invented, including radio telescopes in the 1930s and infrared telescopes in the 1960s; the word telescope now refers to a wide range of instruments capable of detecting different regions of the electromagnetic spectrum, in some cases other types of detectors. The word telescope was coined in 1611 by the Greek mathematician Giovanni Demisiani for one of Galileo Galilei's instruments presented at a banquet at the Accademia dei Lincei.
In the Starry Messenger, Galileo had used the term perspicillum. The earliest existing record of a telescope was a 1608 patent submitted to the government in the Netherlands by Middelburg spectacle maker Hans Lippershey for a refracting telescope; the actual inventor is unknown but word of it spread through Europe. Galileo heard about it and, in 1609, built his own version, made his telescopic observations of celestial objects; the idea that the objective, or light-gathering element, could be a mirror instead of a lens was being investigated soon after the invention of the refracting telescope. The potential advantages of using parabolic mirrors—reduction of spherical aberration and no chromatic aberration—led to many proposed designs and several attempts to build reflecting telescopes. In 1668, Isaac Newton built the first practical reflecting telescope, of a design which now bears his name, the Newtonian reflector; the invention of the achromatic lens in 1733 corrected color aberrations present in the simple lens and enabled the construction of shorter, more functional refracting telescopes.
Reflecting telescopes, though not limited by the color problems seen in refractors, were hampered by the use of fast tarnishing speculum metal mirrors employed during the 18th and early 19th century—a problem alleviated by the introduction of silver coated glass mirrors in 1857, aluminized mirrors in 1932. The maximum physical size limit for refracting telescopes is about 1 meter, dictating that the vast majority of large optical researching telescopes built since the turn of the 20th century have been reflectors; the largest reflecting telescopes have objectives larger than 10 m, work is underway on several 30-40m designs. The 20th century saw the development of telescopes that worked in a wide range of wavelengths from radio to gamma-rays; the first purpose built radio telescope went into operation in 1937. Since a large variety of complex astronomical instruments have been developed; the name "telescope" covers a wide range of instruments. Most detect electromagnetic radiation, but there are major differences in how astronomers must go about collecting light in different frequency bands.
Telescopes may be classified by the wavelengths of light they detect: X-ray telescopes, using shorter wavelengths than ultraviolet light Ultraviolet telescopes, using shorter wavelengths than visible light Optical telescopes, using visible light Infrared telescopes, using longer wavelengths than visible light Submillimetre telescopes, using longer wavelengths than infrared light Fresnel Imager, an optical lens technology X-ray optics, optics for certain X-ray wavelengthsAs wavelengths become longer, it becomes easier to use antenna technology to interact with electromagnetic radiation. The near-infrared can be collected much like visible light, however in the far-infrared and submillimetre range, telescopes can operate more like a radio telescope. For example, the James Clerk Maxwell Telescope observes from wavelengths from 3 μm to 2000 μm, but uses a parabolic aluminum antenna. On the other hand, the Spitzer Space Telescope, observing from about 3 μm to 180 μm uses a mirror. Using reflecting optics, the Hubble Space Telescope with Wide Field Camera 3 can observe in the frequency range from about 0.2 μm to 1.7 μm.
With photons of the shorter wavelengths, with the higher frequencies, glancing-incident optics, rather than reflecting optics are used. Telescopes such as TRACE and SOHO use special mirrors to reflect Extreme ultraviolet, producing higher resolution and brighter images than are otherwise possible. A larger aperture does not just mean that more light is collected, it enables a finer angular resolution. Telescopes may be classified by location: ground telescope, space telescope, or flying telescope, they may be classified by whether they are operated by professional astronomers or amateur astronomers. A vehicle or permanent campus containing one or more telescopes or other instruments is called an observatory. An optical telescope gathers and focuses light from the visible part of the electromagnetic spectrum. Optical telescopes increase the apparent angular size of distant objects as well as their apparent brightness. In order for the image to be observed, photographed and sent to a computer, telescopes work by employing one or
Encyclopædia Britannica, Eleventh Edition
The Encyclopædia Britannica, Eleventh Edition is a 29-volume reference work, an edition of the Encyclopædia Britannica. It was developed during the encyclopaedia's transition from a British to an American publication; some of its articles were written by the best-known scholars of the time. This edition of the encyclopedia, containing 40,000 entries, is now in the public domain, many of its articles have been used as a basis for articles in Wikipedia. However, the outdated nature of some of its content makes its use as a source for modern scholarship problematic; some articles have special value and interest to modern scholars as cultural artifacts of the 19th and early 20th centuries. The 1911 eleventh edition was assembled with the management of American publisher Horace Everett Hooper. Hugh Chisholm, who had edited the previous edition, was appointed editor in chief, with Walter Alison Phillips as his principal assistant editor. Hooper bought the rights to the 25-volume 9th edition and persuaded the British newspaper The Times to issue its reprint, with eleven additional volumes as the tenth edition, published in 1902.
Hooper's association with The Times ceased in 1909, he negotiated with the Cambridge University Press to publish the 29-volume eleventh edition. Though it is perceived as a quintessentially British work, the eleventh edition had substantial American influences, not only in the increased amount of American and Canadian content, but in the efforts made to make it more popular. American marketing methods assisted sales; some 14% of the contributors were from North America, a New York office was established to coordinate their work. The initials of the encyclopedia's contributors appear at the end of selected articles or at the end of a section in the case of longer articles, such as that on China, a key is given in each volume to these initials; some articles were written by the best-known scholars of the time, such as Edmund Gosse, J. B. Bury, Algernon Charles Swinburne, John Muir, Peter Kropotkin, T. H. Huxley, James Hopwood Jeans and William Michael Rossetti. Among the lesser-known contributors were some who would become distinguished, such as Ernest Rutherford and Bertrand Russell.
Many articles were carried over from some with minimal updating. Some of the book-length articles were divided into smaller parts for easier reference, yet others much abridged; the best-known authors contributed only a single article or part of an article. Most of the work was done by British Museum scholars and other scholars; the 1911 edition was the first edition of the encyclopædia to include more than just a handful of female contributors, with 34 women contributing articles to the edition. The eleventh edition introduced a number of changes of the format of the Britannica, it was the first to be published complete, instead of the previous method of volumes being released as they were ready. The print type was subject to continual updating until publication, it was the first edition of Britannica to be issued with a comprehensive index volume in, added a categorical index, where like topics were listed. It was the first not to include long treatise-length articles. Though the overall length of the work was about the same as that of its predecessor, the number of articles had increased from 17,000 to 40,000.
It was the first edition of Britannica to include biographies of living people. Sixteen maps of the famous 9th edition of Stielers Handatlas were translated to English, converted to Imperial units, printed in Gotha, Germany by Justus Perthes and became part this edition. Editions only included Perthes' great maps as low quality reproductions. According to Coleman and Simmons, the content of the encyclopedia was distributed as follows: Hooper sold the rights to Sears Roebuck of Chicago in 1920, completing the Britannica's transition to becoming a American publication. In 1922, an additional three volumes, were published, covering the events of the intervening years, including World War I. These, together with a reprint of the eleventh edition, formed the twelfth edition of the work. A similar thirteenth edition, consisting of three volumes plus a reprint of the twelfth edition, was published in 1926, so the twelfth and thirteenth editions were related to the eleventh edition and shared much of the same content.
However, it became apparent that a more thorough update of the work was required. The fourteenth edition, published in 1929, was revised, with much text eliminated or abridged to make room for new topics; the eleventh edition was the basis of every version of the Encyclopædia Britannica until the new fifteenth edition was published in 1974, using modern information presentation. The eleventh edition's articles are still of value and interest to modern readers and scholars as a cultural artifact: the British Empire was at its maximum, imperialism was unchallenged, much of the world was still ruled by monarchs, the tragedy of the modern world wars was still in the future, they are an invaluable resource for topics omitted from modern encyclopedias for biography and the history of science and technology. As a literary text, the encyclopedia has value as an example of early 20th-century prose. For example, it employs literary devices, such as pathetic fallacy, which are not as common in modern reference texts.
In 1917, using the pseudonym of S. S. Van Dine, the US art critic and author Willard Huntington Wright published Misinforming a Nation, a 200+
A pendulum is a weight suspended from a pivot so that it can swing freely. When a pendulum is displaced sideways from its resting, equilibrium position, it is subject to a restoring force due to gravity that will accelerate it back toward the equilibrium position; when released, the restoring force acting on the pendulum's mass causes it to oscillate about the equilibrium position, swinging back and forth. The time for one complete cycle, a left swing and a right swing, is called the period; the period depends on the length of the pendulum and to a slight degree on the amplitude, the width of the pendulum's swing. From the first scientific investigations of the pendulum around 1602 by Galileo Galilei, the regular motion of pendulums was used for timekeeping, was the world's most accurate timekeeping technology until the 1930s; the pendulum clock invented by Christian Huygens in 1658 became the world's standard timekeeper, used in homes and offices for 270 years, achieved accuracy of about one second per year before it was superseded as a time standard by the quartz clock in the 1930s.
Pendulums are used in scientific instruments such as accelerometers and seismometers. They were used as gravimeters to measure the acceleration of gravity in geophysical surveys, as a standard of length; the word "pendulum" is new Latin, from the Latin pendulus, meaning'hanging'. The simple gravity pendulum is an idealized mathematical model of a pendulum; this is a weight on the end of a massless cord suspended without friction. When given an initial push, it will swing forth at a constant amplitude. Real pendulums are subject to friction and air drag, so the amplitude of their swings declines; the period of swing of a simple gravity pendulum depends on its length, the local strength of gravity, to a small extent on the maximum angle that the pendulum swings away from vertical, θ0, called the amplitude. It is independent of the mass of the bob. If the amplitude is limited to small swings, the period T of a simple pendulum, the time taken for a complete cycle, is: T ≈ 2 π L g θ 0 ≪ 1 r a d i a n where L is the length of the pendulum and g is the local acceleration of gravity.
For small swings the period of swing is the same for different size swings: that is, the period is independent of amplitude. This property, called isochronism, is the reason. Successive swings of the pendulum if changing in amplitude, take the same amount of time. For larger amplitudes, the period increases with amplitude so it is longer than given by equation. For example, at an amplitude of θ0 = 23 ° it is 1 % larger; the period increases asymptotically as θ0 approaches 180°, because the value θ0 = 180° is an unstable equilibrium point for the pendulum. The true period of an ideal simple gravity pendulum can be written in several different forms, one example being the infinite series: T = 2 π L g where θ 0 is in radians; the difference between this true period and the period for small swings above is called the circular error. In the case of a typical grandfather clock whose pendulum has a swing of 6° and thus an amplitude of 3°, the difference between the true period and the small angle approximation amounts to about 15 seconds per day.
For small swings the pendulum approximates a harmonic oscillator, its motion as a function of time, t, is simple harmonic motion: θ = θ 0 cos where φ is a constant value, dependent on initial conditions. For real pendulums, the period varies with factors such as the buoyancy and viscous resistance of the air, the mass of the string or rod, the size and shape of the bob and how it is attached to the string, flexibility and stretching of the string. In precision applications, corrections for these factors may need to be applied to eq. to give the period accurately. Any swinging rigid body free to rotate about a fixed horizontal axis is called a compound pendulum or physical pendulum; the appropriate equivalent length L for calculating the period of any such pendulum is the distance from the pivot to the center of oscillation. This point is located under the center of mass at a distance from the pivot traditionally called the radius of oscillation, which depends on the mass distribution of the pendulum.
If most of the mass is concentrated in a small bob compared to the pendulum length, the center of oscillation is close to the center of mass. The radiu
Eustachio Divini was an Italian manufacturer and experimenter of optical instruments for scientific use in Rome. Eustachio was born on 4 October 1610 in San Severino Marche, from the illustrious Divini's family. At the age of 4 his mother, Virginia Saracini, died and 7 years his father, Tardozzo Divini died, so his brothers Vincenzo and Cipriano looked after him and his basic education before moving to Rome. At that time Divini was initiated into the military career but after a severe disease in 1629 he had to give up. After that he joined again his brothers, his brother Vincenzo, who frequented the literary and scientific circle in Rome, incited him to follow the lessons of monk Benedetto Castelli, disciple of Galilei. So Eustachio began his new fertile formative experience with people of his same generation such as Evangelista Torricelli, Alfonso Borelli, Bonaventura Cavalieri and Michelangelo Ricci. In the early 1640s Divini practiced as a clock-maker. Subsequently, his good relationship and friendship with Torricelli led him to cultivate a shared interest, the construction of optical instruments and telescopes and their improvement.
Divini's factory of instruments was located in the area of Navona square in Rome, it is probable that quite a high number of artisans where working under Divini's direction. Since 1646 to about mid-century his lenses and glasses spread all over Europe granting him the role of Italy's foremost optician. Many types of telescopes of various lengths were owned by prominent secular and ecclesiastic authorities in Rome. Divini's reputation and earnings were obtained not only thanks to the manufacture of optical instruments, but thanks to the frequenting of a circle of scholars of the Roman College, where the astronomical research and the quality of the instruments of observation were both important. Differently from Francini, Galilei’s artisan, this group produced new working methods and new optical systems; these discoveries were spread all over Europe. The Court of Medici in Florence bought many Divini's telescopes and was not only a test bench for him, but a spreading engine for the notoriety of the optician, because of the role of the associated Accademia del Cimento in triggering astronomical research in all Europe.
So it isn’t a surprise that the prestigious Science Academy of London dedicated to Divini with the inscription: "Divinus Eustachius De Sancto Severini, Insignis Mathematicus". It should be noted, that the astronomers of the Accademia del Cimento substituted several Divini's objectives for Torricelli's lenses, obtaining a perfect combination with Divini's convex oculars and composed eyepieces. Recent tests and analysis of telescopes conserved in Florence Science Museum confirm these changes on Divini's telescopes and the better quality of Torricelli's objective lenses. Divini's first publication was a print appeared in 1649 where he intended to document the possibilities offered by his telescopes. Indeed, at the centre he depicted a selenography derived from his observations of the full moon in March 1649, using two telescopes, around the crescent Saturn and Jupiter, he deserved fame for his use of micrometer eyepiece consisting in a grid of wires inserted in a biconvex eyepiece, thanks to which he could draw the moonspots in the exact position.
A copy of that selenography was given by Eustachio Divini to his hometown San Severino, his birth town he kept in touch continuously together with his brother Cipriano, a well-established painter in Rome. Divini's contributes to microscope optics and mechanics, shared with Campani brothers, are unquestionable, he designed, among the others, coupled lenses to reduce chromatic aberration, devised a mirror to send light onto the specimen to be observed, created the Vase microscope. Quoted for having been used by Malpighi in his discovery of red blood cells flowing in capillaries around 1660. Eustachio Divini re-discovered the spot, the satellites shadows and the changing shape belt upon Jupiter in 1665, with his telescopes; these discoveries had permitted to argue out the rotation of Jupiter around its axis, whereas Divini was able to demonstrate the amateurs and astronomers community that his instruments were as effective as the ones made by his rivals, Campani brothers, manufacturer of telescopes for Cassini.
It was around the middle of seventieth century, after the development of telescope handicraft initiated by Galilei, Fontana and others, that direct comparisons of telescopes – paragoni – became regular and exciting events in the Italian world of science hailed by the Accademia del Cimento in Florence, one of the earliest societies dedicated to the experimental method. Eustachio Divini was one of the most relevant protagonists, against his will, of these contests, and he was the most honest of all competitors because of his fair and humble nature that prevented him to defraud the tests or to put forward mysterious theoretical reasons based on the laws of optics, to praise his lenses and instruments, as was done by more famous scientists. Divini was sponsor and promoter of himself, based on his expertise and messages of superior quality that his lenses directly communicated to their owners in all Europe. Divini's reputation as the best European maker of telescopes begun to be superseded in 1656, when Christiaan Huygens announced the discovery of a "moon" of Saturn.
The Dutch astronomer, discovered it in 1655 using his own telescopes followed its movements for months
Italy the Italian Republic, is a country in Southern Europe. Located in the middle of the Mediterranean Sea, Italy shares open land borders with France, Austria and the enclaved microstates San Marino and Vatican City. Italy covers an area of 301,340 km2 and has a temperate seasonal and Mediterranean climate. With around 61 million inhabitants, it is the fourth-most populous EU member state and the most populous country in Southern Europe. Due to its central geographic location in Southern Europe and the Mediterranean, Italy has been home to a myriad of peoples and cultures. In addition to the various ancient peoples dispersed throughout modern-day Italy, the most famous of which being the Indo-European Italics who gave the peninsula its name, beginning from the classical era and Carthaginians founded colonies in insular Italy and Genoa, Greeks established settlements in the so-called Magna Graecia, while Etruscans and Celts inhabited central and northern Italy respectively; the Italic tribe known as the Latins formed the Roman Kingdom in the 8th century BC, which became a republic with a government of the Senate and the People.
The Roman Republic conquered and assimilated its neighbours on the peninsula, in some cases through the establishment of federations, the Republic expanded and conquered parts of Europe, North Africa and the Middle East. By the first century BC, the Roman Empire emerged as the dominant power in the Mediterranean Basin and became the leading cultural and religious centre of Western civilisation, inaugurating the Pax Romana, a period of more than 200 years during which Italy's technology, economy and literature flourished. Italy remained the metropole of the Roman Empire; the legacy of the Roman Empire endured its fall and can be observed in the global distribution of culture, governments and the Latin script. During the Early Middle Ages, Italy endured sociopolitical collapse and barbarian invasions, but by the 11th century, numerous rival city-states and maritime republics in the northern and central regions of Italy, rose to great prosperity through shipping and banking, laying the groundwork for modern capitalism.
These independent statelets served as Europe's main trading hubs with Asia and the Near East enjoying a greater degree of democracy than the larger feudal monarchies that were consolidating throughout Europe. The Renaissance began in Italy and spread to the rest of Europe, bringing a renewed interest in humanism, science and art. Italian culture flourished, producing famous scholars and polymaths such as Michelangelo, Leonardo da Vinci, Raphael and Machiavelli. During the Middle Ages, Italian explorers such as Marco Polo, Christopher Columbus, Amerigo Vespucci, John Cabot and Giovanni da Verrazzano discovered new routes to the Far East and the New World, helping to usher in the European Age of Discovery. Italy's commercial and political power waned with the opening of trade routes that bypassed the Mediterranean. Centuries of infighting between the Italian city-states, such as the Italian Wars of the 15th and 16th centuries, left the region fragmented, it was subsequently conquered and further divided by European powers such as France and Austria.
By the mid-19th century, rising Italian nationalism and calls for independence from foreign control led to a period of revolutionary political upheaval. After centuries of foreign domination and political division, Italy was entirely unified in 1871, establishing the Kingdom of Italy as a great power. From the late 19th century to the early 20th century, Italy industrialised, namely in the north, acquired a colonial empire, while the south remained impoverished and excluded from industrialisation, fuelling a large and influential diaspora. Despite being one of the main victors in World War I, Italy entered a period of economic crisis and social turmoil, leading to the rise of a fascist dictatorship in 1922. Participation in World War II on the Axis side ended in military defeat, economic destruction and the Italian Civil War. Following the liberation of Italy and the rise of the resistance, the country abolished the monarchy, reinstated democracy, enjoyed a prolonged economic boom and, despite periods of sociopolitical turmoil became a developed country.
Today, Italy is considered to be one of the world's most culturally and economically advanced countries, with the sixth-largest worldwide national wealth. Its advanced economy ranks eighth-largest in the world and third in the Eurozone by nominal GDP. Italy owns the third-largest central bank gold reserve, it has a high level of human development, it stands among the top countries for life expectancy. The country plays a prominent role in regional and global economic, military and diplomatic affairs. Italy is a founding and leading member of the European Union and a member of numerous international institutions, including the UN, NATO, the OECD, the OSCE, the WTO, the G7, the G20, the Union for the Mediterranean, the Council of Europe, Uniting for Consensus, the Schengen Area and many more; as a reflection
Rome is the capital city and a special comune of Italy. Rome serves as the capital of the Lazio region. With 2,872,800 residents in 1,285 km2, it is the country's most populated comune, it is the fourth most populous city in the European Union by population within city limits. It is the centre of the Metropolitan City of Rome, which has a population of 4,355,725 residents, thus making it the most populous metropolitan city in Italy. Rome is located in the central-western portion of the Italian Peninsula, within Lazio, along the shores of the Tiber; the Vatican City is an independent country inside the city boundaries of Rome, the only existing example of a country within a city: for this reason Rome has been defined as capital of two states. Rome's history spans 28 centuries. While Roman mythology dates the founding of Rome at around 753 BC, the site has been inhabited for much longer, making it one of the oldest continuously occupied sites in Europe; the city's early population originated from a mix of Latins and Sabines.
The city successively became the capital of the Roman Kingdom, the Roman Republic and the Roman Empire, is regarded by some as the first metropolis. It was first called The Eternal City by the Roman poet Tibullus in the 1st century BC, the expression was taken up by Ovid and Livy. Rome is called the "Caput Mundi". After the fall of the Western Empire, which marked the beginning of the Middle Ages, Rome fell under the political control of the Papacy, in the 8th century it became the capital of the Papal States, which lasted until 1870. Beginning with the Renaissance all the popes since Nicholas V pursued over four hundred years a coherent architectural and urban programme aimed at making the city the artistic and cultural centre of the world. In this way, Rome became first one of the major centres of the Italian Renaissance, the birthplace of both the Baroque style and Neoclassicism. Famous artists, painters and architects made Rome the centre of their activity, creating masterpieces throughout the city.
In 1871, Rome became the capital of the Kingdom of Italy, which, in 1946, became the Italian Republic. Rome has the status of a global city. In 2016, Rome ranked as the 14th-most-visited city in the world, 3rd most visited in the European Union, the most popular tourist attraction in Italy, its historic centre is listed by UNESCO as a World Heritage Site. The famous Vatican Museums are among the world's most visited museums while the Colosseum was the most popular tourist attraction in world with 7.4 million visitors in 2018. Host city for the 1960 Summer Olympics, Rome is the seat of several specialized agencies of the United Nations, such as the Food and Agriculture Organization, the World Food Programme and the International Fund for Agricultural Development; the city hosts the Secretariat of the Parliamentary Assembly of the Union for the Mediterranean as well as the headquarters of many international business companies such as Eni, Enel, TIM, Leonardo S.p. A. and national and international banks such as Unicredit and BNL.
Its business district, called EUR, is the base of many companies involved in the oil industry, the pharmaceutical industry, financial services. Rome is an important fashion and design centre thanks to renowned international brands centered in the city. Rome's Cinecittà Studios have been the set of many Academy Award–winning movies. According to the founding myth of the city by the Ancient Romans themselves, the long-held tradition of the origin of the name Roma is believed to have come from the city's founder and first king, Romulus. However, it is a possibility that the name Romulus was derived from Rome itself; as early as the 4th century, there have been alternative theories proposed on the origin of the name Roma. Several hypotheses have been advanced focusing on its linguistic roots which however remain uncertain: from Rumon or Rumen, archaic name of the Tiber, which in turn has the same root as the Greek verb ῥέω and the Latin verb ruo, which both mean "flow". There is archaeological evidence of human occupation of the Rome area from 14,000 years ago, but the dense layer of much younger debris obscures Palaeolithic and Neolithic sites.
Evidence of stone tools and stone weapons attest to about 10,000 years of human presence. Several excavations support the view that Rome grew from pastoral settlements on the Palatine Hill built above the area of the future Roman Forum. Between the end of the bronze age and the beginning of the Iron age, each hill between the sea and the Capitol was topped by a village. However, none of them had yet an urban quality. Nowadays, there is a wide consensus that the city developed through the aggregation of several villages around the largest one, placed above the Palatine; this aggregation was facilitated by the increase of agricultural productivity above the subsistence level, which allowed the establishment of secondary and tertiary activities. These in turn boosted the development of trade with the Greek colonies of southern Italy; these developments, which according to archaeological ev
Spoleto is an ancient city in the Italian province of Perugia in east-central Umbria on a foothill of the Apennines. It is 29 km N. of Terni, 63 km SE of Perugia. Spoleto was situated on the eastern branch of the Via Flaminia, which forked into two roads at Narni and rejoined at Forum Flaminii, near Foligno. An ancient road ran hence to Nursia; the Ponte Sanguinario of the 1st century BC still exists. The Forum lies under today's marketplace. Located at the head of a large, broad valley, surrounded by mountains, Spoleto has long occupied a strategic geographical position, it appears to have been an important town to the original Umbri tribes, who built walls around their settlement in the 5th century BC, some of which are visible today. The first historical mention of Spoletium is the notice of the foundation of a colony there in 241 BC. After the Battle of Lake Trasimene Spoletium was attacked by Hannibal, repulsed by the inhabitants During the Second Punic War the city was a useful ally to Rome.
It suffered during the civil wars of Gaius Marius and Sulla. The latter, after his victory over Marius, confiscated the territory of Spoletium. From this time forth it was a municipium. Under the empire it seems to have flourished once again, but is not mentioned in history. Martial speaks of its wine. Aemilianus, proclaimed emperor by his soldiers in Moesia, was slain by them here on his way from Rome, after a reign of three or four months. Rescripts of Constantine and Julian are dated from Spoleto; the foundation of the episcopal see dates from the 4th century: early martyrs of Spoleto are legends, but a letter to the bishop Caecilianus, from Pope Liberius in 354 constitutes its first historical mention. Owing to its elevated position Spoleto was an important stronghold during the Vandal and Gothic wars. Under the Lombards, Spoleto became the capital of an independent duchy, the Duchy of Spoleto, its dukes ruled a considerable part of central Italy. In 774 it became part of Holy Roman Empire. Several of its dukes during the late 9th Century, rose to wear the crown of that Empire.
Together with other fiefs, it was bequeathed to Pope Gregory VII by the powerful countess Matilda of Tuscany, but for some time struggled to maintain its independence. In 1155 it was destroyed by Frederick Barbarossa. In 1213 it was definitively occupied by Pope Gregory IX. During the absence of the papal court in Avignon, it was prey to the struggles between Guelphs and Ghibellines, until in 1354 Cardinal Albornoz brought it once more under the authority of the Papal States. After Napoleon's conquest of Italy, in 1809 Spoleto became capital of the short-lived French department of Trasimène, returning to the Papal States after Napoleon's defeat, within five years. In 1860, after a gallant defence, Spoleto was taken by the troops fighting for the unification of Italy. Giovanni Pontano, founder of the Accademia Pontaniana of Naples, was born here. Another child of Spoleto was Francis Possenti, educated in the Jesuit school and whose father was the Papal assessor, Francis entered the Passionists and became Saint Gabriel of Our Lady of Sorrows.
The Roman theater rebuilt. The stage is occupied by the former church of St. Agatha housing the National Archaeological Museum. Ponte Sanguinario, a Roman bridge 1st century BCE; the name is traditionally attributed to the persecutions of Christians in the nearby amphiteatre. A restored Roman house with mosaic floors, indicating it was built in the 1st century, overlooked the Forum Square. An inscription by Polla to Emperor Caligula suggests the house was that of Vespasia Polla, the mother of Emperor Vespasian. Roman amphitheater, it was turned into a fortress by Totila in 545 and in Middle Ages times was used for stores and shops, while in the cavea the church of San Gregorio Minore was built. The stones were used to build the Rocca; the Palazzo Comunale. Ponte delle Torri, a striking 13th-century aqueduct on Roman foundations: whether it was first built by the Romans is a point on which scholarly opinion is divided; the majestic Rocca Albornoziana fortress, built in 1359–1370 by the architect Matteo Gattapone of Gubbio for Cardinal Albornoz.
It has six sturdy towers which formed two distinct inner spaces: the Cortile delle Armi, for the troops, the Cortile d'onore for the use of the city's governor. The latter courtyard is surrounded by a two-floor porch; the rooms include the Camera Pinta with noteworthy 15th‑century frescoes. After having resisted many sieges, the Rocca was turned into a jail in 1800 and used as such until the late 20th century. After extensive renovation it was reopened as a museum in 2007; the Palazzo Racani-Arroni has a worn graffito decoration attributed to Giulio Romano. The inner courtyard has a notable fountain. Palazzo della Signoria, housing the city's museum; the majestic Palazzo Vigili includes the Torre dell'Olio, the sole mediaeval city tower remaining in Spoleto. Temple of Clitumnus lies between Spoleto and Trevi Duomo of S. Maria Assunta: Construction of the Duomo begun around 1175 and completed in 1227; the Romanesque edifice contains the tomb of Filippo Lippi, who died in Spoleto in 1469, designed by his son Filippino Lippi.
The church houses a manuscript letter by Saint Francis of Assisi. San Pietro extra Moenia: This church was founded in 4