John Harrison was a self-educated English carpenter and clockmaker who invented the marine chronometer, a long-sought-after device for solving the problem of calculating longitude while at sea. Harrison's solution revolutionized navigation and increased the safety of long-distance sea travel; the problem he solved was considered so important following the Scilly naval disaster of 1707 that the British Parliament offered financial rewards of up to £20,000 under the 1714 Longitude Act. In 1730, Harrison presented his first design, worked over many years on improved designs, making several advances in time-keeping technology turning to what were called sea watches. Harrison gained support from the Longitude Board in testing his designs. Toward the end of his life, he received a reward from Parliament. Harrison came 39th in the BBC's 2002 public poll of the 100 Greatest Britons. John Harrison was born in Foulby in the West Riding of Yorkshire, the first of five children in his family, his step father worked as a carpenter at the nearby Nostell Priory estate.
A house on the site of what may have been the family home bears a blue plaque. Around 1700, the Harrison family moved to the Lincolnshire village of Barrow upon Humber. Following his father's trade as a carpenter, Harrison built and repaired clocks in his spare time. Legend has it that at the age of six, while in bed with smallpox, he was given a watch to amuse himself and he spent hours listening to it and studying its moving parts, he had a fascination for music becoming choirmaster for Barrow parish church. Harrison built his first longcase clock in 1713, at the age of 20; the mechanism was made of wood. Three of Harrison's early wooden clocks have survived: the first is in the Worshipful Company of Clockmakers' collection in the Guildhall in London, since 2015 on display in the Science Museum; the second is in the Science Museum in London. The Nostell example, in the billiards room of this stately home, has a Victorian outer case, which has small glass windows on each side of the movement so that the wooden workings may be inspected.
In the early 1720s, Harrison was commissioned to make a new turret clock at Brocklesby Park, North Lincolnshire. The clock still works, like his previous clocks has a wooden movement of oak and lignum vitae. Unlike his early clocks, it incorporates some original features to improve timekeeping, for example the grasshopper escapement. Between 1725 and 1728, John and his brother James a skilled joiner, made at least three precision longcase clocks, again with the movements and longcase made of oak and lignum vitae; the grid-iron pendulum was developed during this period. These precision clocks are thought by some to have been the most accurate clocks in the world at the time. Number 1, now in a private collection, belonged to the Time Museum, USA, until the museum closed in 2000 and its collection was dispersed at auction in 2004. Number 2 is in the Leeds City Museum, it forms the core of a permanent display dedicated to John Harrison's achievements, "John Harrison: The Clockmaker Who Changed the World" and had its official opening on 23 January 2014, the first longitude-related event marking the tercentenary of the Longitude Act.
Number 3 is in the Worshipful Company of Clockmakers' collection. Harrison was a man of many skills and he used these to systematically improve the performance of the pendulum clock, he invented the gridiron pendulum, consisting of alternating brass and iron rods assembled so that the thermal expansions and contractions cancel each other out. Another example of his inventive genius was the grasshopper escapement – a control device for the step-by-step release of a clock's driving power. Developed from the anchor escapement, it was frictionless, requiring no lubrication because the pallets were made from wood; this was an important advantage at a time when lubricants and their degradation were little understood. In his earlier work on sea clocks, Harrison was continually assisted, both financially and in many other ways, by George Graham, the watchmaker and instrument maker. Harrison was introduced to Graham by the Astronomer Royal Edmond Halley, who championed Harrison and his work; this support was important to Harrison, as he was supposed to have found it difficult to communicate his ideas in a coherent manner.
Longitude fixes the location of a place on Earth east or west of a north-south line called the prime meridian. It is given as an angular measurement that ranges from 0° at the prime meridian to +180° eastward and −180° westward. Knowledge of a ship's east-west position was essential. After a long voyage, cumulative errors in dead reckoning led to shipwrecks and a great loss of life. Avoiding such disasters became vital in Harrison's lifetime, in an era when trade and navigation were increasing around the world. Many ideas were proposed for. Earlier methods attempted to compare local time with the known time at a reference place, such as Greenwich or Paris, based on a simple theory, first proposed by Gemma Frisius; the methods relied on astronomical observations that were themselves reliant on the predictable nature of the motions of different heavenly bodies. Such methods were problematic because of the difficulty in estimating the time at the reference place. Harrison set out to solve the problem directly, by producing a reliable clock that could keep the time of the reference place.
His difficulty was in producing a clock tha
Navigational Algorithms is a web site whose purpose is to make available the scientific part of the art of navigation, containing specialized articles and software that implements the various procedures of calculus. The topics covered are: Celestial navigation: Sight reduction, circle of equal altitude, Line Of Position, Fix... Positional astronomy: RA, GHA, Dec Coastal navigation: Range, Horizontal angles, IALA... Sailings: Rhumbs, Orthodromic, Meridional parts... Weather, tides Software PC- PDA: Nautical Almanac, Variation, Sextant corrections Include articles about piloting and astronavigation: Corrections for sextant altitude, Sight Reduction with calculator-Form & Plotting sheet for celestial LoPs, Celestial Fix - 2 LoPs, Celestial Fix - n LoPs NA Sight Reduction algorithm, Vector equation of the Circle of equal altitude, Vector Solution for the intersection of two Circles of Equal Altitude, Sight Reduction - Matrix solution. Include papers about introduction to navigation, naval kinematics and oceanography This section gives a brief description of the free programs available for navigation.
Run under Windows XP, Ephemerides of the celestial bodies used in navigation. GHA - Greenwich Hour Angle Dec - Declination SD - Semidiameter HP - Horizontal Parallax Astronavigation solution for sight reduction for n observations made with a marine sextant & running fixes The algorithms implemented are: For n = 2 observations An analytical solution of the two star sight problem of celestial navigation, James A. Van Allen. Vector Solution for the Intersection of two Circles of Equal Altitude. Andrés Ruiz. For n ≥ 2 observations DeWit/USNO Nautical Almanac/Compac Data, Least squares algorithm for n LOPs Kaplan algorithm, USNO. For n ≥ 8 observations, gives the solution for course and SOG. Any measure of course made with a magnetic compass must be corrected because of the magnetic declination or local variation. Navigation Celestial navigation Nautical almanac Lunar distance Sextant American Practical Navigator Rhumbline network Royal Institute of Navigation Institute of Navigation Shortest path problem and automotive navigation, for navigational algorithms in other domains.
The intercept method known as Marcq St. Hilaire method, is an astronomical navigation method of calculating an observer's position on earth, it was called the azimuth intercept method because the process involves drawing a line which intercepts the azimuth line. This name was shortened to intercept method and the intercept distance was shortened to'intercept'; the method yields a line of position. The intersection of two or more such lines will define the observer's position, called a "fix". Sights may be taken at short intervals during hours of twilight, or they may be taken at an interval of an hour or more. In either case, the lines of position, if taken at different times, must be advanced or retired to correct for the movement of the ship during the interval between observations. If observations are taken at short intervals, a few minutes at most, the corrected lines of position by convention yield a "fix". If the lines of position must be advanced or retired by an hour or more, convention dictates that the result is referred to as a "running fix".
The intercept method is based on the following principle. The actual distance from the observer to the geographical position of a celestial body is "measured" using a sextant; the observer has estimated his position by dead reckoning and calculated the distance from the estimated position to the body's GP. The diagram on the right shows why the zenith distance of a celestial body is equal to the angular distance of its GP from the observer's position; the rays of light from a celestial body are assumed to be parallel. The angle at the centre of the Earth that the ray of light passing through the body's GP makes with the line running from the observer's zenith is the same as the zenith distance; this is. In practice it is not necessary to use zenith distances, which are 90° minus altitude, as the calculations can be done using observed altitude and calculated altitude. Taking a sight using the intercept method consists of the following process: Observe the altitude above the horizon Ho of a celestial body and note the time of the observation.
Assume a certain geographical position, it does not matter which one so long as it is within, say, 50 NM of the actual position. Compute the altitude Hc and azimuth Zn with which an observer situated at that assumed position would observe the body. If the actual observed altitude Ho is smaller than the computed altitude Hc this means the observer is farther away from the body than the observer at the assumed position, vice versa. For each minute of arc the distance is one NM and the difference between Hc and Ho expressed in minutes of arc is termed the "intercept"; the navigator now has computed the azimuth of the body. On the chart he draws a line in the direction of the azimuth Zn, he measures the intercept distance along this azimuth line, towards the body if Ho>Hc and away from it if Ho<Hc. At this new point he draws a perpendicular to the azimuth line and, the line of position LOP at the moment of the observation; the reason that the chosen AP is not important is that if a position closer to the body is chosen Hc will be greater but the distance will be measured from the new AP, closer to the body and the end resulting LOP will be the same.
Suitable bodies for celestial sights are selected using a Rude Star Finder. Using a sextant, an altitude is obtained of the moon, a star or a planet; the name of the body and the precise time of the sight in UTC is recorded. The sextant is read and the altitude of the body is recorded. Once all sights are taken and recorded, the navigator is ready to start the process of sight reduction and plotting; the first step in sight reduction is to correct the sextant altitude for various errors and corrections. The instrument may have IC or index correction. Refraction by the atmosphere is corrected for with the aid of a table or calculation and the observer's height of eye above sea level results in a "dip" correction. If the Sun or Moon was observed, a semidiameter correction is applied to find the centre of the object; the resulting value is "observed altitude". Next, using an accurate clock, the observed celestial object's geographic position is looked up in an almanac. That's the point on the Earth's surface directly below it.
The latitude of the geographic position is called declination, the longitude is called the hour angle. Next, the altitude and azimuth of the celestial body are computed for a selected position; this involves resolving a spherical triangle. Given the three magnitudes: local hour angle, observed body's declination, assumed latitude, the altitude Hc and azimuth Zn must be computed; the local hour angle, LHA, is the difference between the AP longitude and the hour angle of the observed object. It is always measured in a westerly direction from the assumed position; the relevant formulas are: sin = sin ⋅ sin
A marine chronometer is a timepiece, precise and accurate enough to be used as a portable time standard. When first developed in the 18th century, it was a major technical achievement, as accurate knowledge of the time over a long sea voyage is necessary for navigation, lacking electronic or communications aids; the first true chronometer was the life work of one man, John Harrison, spanning 31 years of persistent experimentation and testing that revolutionized naval navigation and enabling the Age of Discovery and Colonialism to accelerate. The term chronometer was coined from the Greek words chronos and meter in 1714 by Jeremy Thacker, an early competitor for the prize set by the Longitude Act in the same year, it has become more used to describe watches tested and certified to meet certain precision standards. Timepieces made in Switzerland may display the word "chronometer" only if certified by the COSC. To determine a position on the Earth's surface, it is necessary and sufficient to know the latitude and altitude.
Altitude considerations can be ignored for vessels operating at sea level. Until the mid-1750s, accurate navigation at sea out of sight of land was an unsolved problem due to the difficulty in calculating longitude. Navigators could determine their latitude by measuring the sun's angle at noon or, in the Northern Hemisphere, to measure the angle of Polaris from the horizon. To find their longitude, they needed a time standard that would work aboard a ship. Observation of regular celestial motions, such as Galileo's method based on observing Jupiter's natural satellites, was not possible at sea due to the ship's motion; the lunar distances method proposed by Johannes Werner in 1514, was developed in parallel with the marine chronometer. The Dutch scientist Gemma Frisius was the first to propose the use of a chronometer to determine longitude in 1530; the purpose of a chronometer is to measure the time of a known fixed location, for example Greenwich Mean Time. This is important for navigation. Knowing GMT at local noon allows a navigator to use the time difference between the ship's position and the Greenwich Meridian to determine the ship's longitude.
As the Earth rotates at a regular rate, the time difference between the chronometer and the ship's local time can be used to calculate the longitude of the ship relative to the Greenwich Meridian using spherical trigonometry. In modern practice, a nautical almanac and trigonometric sight-reduction tables permit navigators to measure the Sun, visible planets, or any of 57 selected stars for navigation at any time that the horizon is visible; the creation of a timepiece which would work reliably at sea was difficult. Until the 20th century, the best timekeepers were pendulum clocks, but both the rolling of a ship at sea and the up to 0.2% variations in the gravity of Earth made a simple gravity-based pendulum useless both in theory and in practice. Christiaan Huygens, following his invention of the pendulum clock in 1656, made the first attempt at a marine chronometer in 1673 in France, under the sponsorship of Jean-Baptiste Colbert. In 1675, receiving a pension from Louis XIV, invented a chronometer that employed a balance wheel and a spiral spring for regulation, instead of a pendulum, opening the way to marine chronometers and modern pocket watches and wristwatches.
He obtained a patent for his invention from Colbert. Huygens' attempt in 1675 to obtain an English patent from Charles II stimulated Robert Hooke, who claimed to have conceived of a spring-driven clock years earlier, to attempt to produce one and patent it. During 1675 Huygens and Hooke each delivered two such devices to Charles, but none worked well and neither Huygens nor Hooke received an English patent, it was during this work. The first published use of the term was in 1684 in Arcanum Navarchicum, a theoretical work by Kiel professor Matthias Wasmuth; this was followed by a further theoretical description of a chronometer in works published by English scientist William Derham in 1713. Derham's principal work, Physico-theology, or a demonstration of the being and attributes of God from his works of creation proposed the use of vacuum sealing to ensure greater accuracy in the operation of clocks. Attempts to construct a working marine chronometer were begun by Jeremy Thacker in England in 1714, by Henry Sully in France two years later.
Sully published his work in 1726 with Une Horloge inventée et executée par M. Sulli, but neither his nor Thacker's models were able to resist the rolling of the seas and keep precise time while in shipboard conditions. In 1714, the British government offered a longitude prize for a method of determining longitude at sea, with the awards ranging from £10,000 to £20,000 depending on accuracy. John Harrison, a Yorkshire carpenter, submitted a project in 1730, in 1735 completed a clock based on a pair of counter-oscillating weighted beams connected by springs whose motion was not influenced by gravity or the motion of a ship, his first two sea timepieces H1 and H2 used this system, but he realised that they had a fundamental sensitivity to centrifugal force, which meant that they could never be accurate enough at sea. Construction
A prime meridian is a meridian in a geographic coordinate system at which longitude is defined to be 0°. Together, a prime meridian and its anti-meridian form a great circle; this great circle divides e.g. Earth, into two hemispheres. If one uses directions of East and West from a defined prime meridian they can be called the Eastern Hemisphere and the Western Hemisphere. A prime meridian is arbitrary, unlike an equator, determined by the axis of rotation—and various conventions have been used or advocated in different regions and throughout history; the most used modern meridian is the IERS Reference Meridian. It is derived but deviates from the Greenwich Meridian, selected as an international standard in 1884; the notion of longitude was developed by the Greek Eratosthenes in Alexandria, Hipparchus in Rhodes, applied to a large number of cities by the geographer Strabo. But it was Ptolemy. Ptolemy used as his basis the "Fortunate Isles", a group of islands in the Atlantic which are associated with the Canary Islands, although his maps correspond more to the Cape Verde islands.
The main point is to be comfortably west of the western tip of Africa as negative numbers were not yet in use. His prime meridian corresponds to 18° 40' west of Winchester today. At that time the chief method of determining longitude was by using the reported times of lunar eclipses in different countries. Ptolemy's Geographia was first printed with maps at Bologna in 1477, many early globes in the 16th century followed his lead, but there was still a hope. Christopher Columbus reported that the compass pointed due north somewhere in mid-Atlantic, this fact was used in the important Treaty of Tordesillas of 1494 which settled the territorial dispute between Spain and Portugal over newly discovered lands; the Tordesillas line was settled at 370 leagues west of Cape Verde. This is shown in Diogo Ribeiro's 1529 map. São Miguel Island in the Azores was still used for the same reason as late as 1594 by Christopher Saxton, although by it had been shown that the zero magnetic deviation line did not follow a line of longitude.
In 1541, Mercator produced his famous 41 cm terrestrial globe and drew his prime meridian through Fuerteventura in the Canaries. His maps used the Azores, following the magnetic hypothesis, but by the time that Ortelius produced the first modern atlas in 1570, other islands such as Cape Verde were coming into use. In his atlas longitudes were counted from 0° to 360°, not 180°W to 180°E as is usual today; this practice was followed by navigators well into the 18th century. In 1634, Cardinal Richelieu used the westernmost island of the Canaries, Ferro, 19° 55' west of Paris, as the choice of meridian; the geographer Delisle decided to round this off to 20°, so that it became the meridian of Paris disguised. In the early 18th century the battle was on to improve the determination of longitude at sea, leading to the development of the marine chronometer by John Harrison, but it was the development of accurate star charts, principally by the first British Astronomer Royal, John Flamsteed between 1680 and 1719 and disseminated by his successor Edmund Halley, that enabled navigators to use the lunar method of determining longitude more using the octant developed by Thomas Godfrey and John Hadley.
Between 1765 and 1811, Nevil Maskelyne published 49 issues of the Nautical Almanac based on the meridian of the Royal Observatory, Greenwich. "Maskelyne's tables not only made the lunar method practicable, they made the Greenwich meridian the universal reference point. The French translations of the Nautical Almanac retained Maskelyne's calculations from Greenwich—in spite of the fact that every other table in the Connaissance des Temps considered the Paris meridian as the prime." In 1884, at the International Meridian Conference in Washington, D. C. 22 countries voted to adopt the Greenwich meridian as the prime meridian of the world. The French argued for a neutral line, mentioning the Azores and the Bering Strait, but abstained and continued to use the Paris meridian until 1911. In October 1884 the Greenwich Meridian was selected by delegates to the International Meridian Conference held in Washington, D. C. United States to be the common zero of longitude and standard of time reckoning throughout the world.
The modern prime meridian, the IERS Reference Meridian, is placed near this meridian and is the prime meridian that has the widest use. The modern prime meridian, based at the Royal Observatory, was established by Sir George Airy in 1851; the position of the Greenwich Meridian has been defined by the location of the Airy Transit Circle since the first observation was taken with it by Sir George Airy in 1851. Prior to that, it was defined by a succession of earlier transit instruments, the first of, acquired by the second Astronomer Royal, Edmond Halley in 1721, it was set up in the extreme north-west corner of the Observatory between Flamsteed House and the Western Summer House. This spot, now subsumed into Flamsteed House, is 43 metres to the west of the Airy Transit Circle, a distance equivalent to 0.15 seconds of time. It was Airy's transit circle, adopted in principle as the Prime Meridian of th
Navigation is a field of study that focuses on the process of monitoring and controlling the movement of a craft or vehicle from one place to another. The field of navigation includes four general categories: land navigation, marine navigation, aeronautic navigation, space navigation, it is the term of art used for the specialized knowledge used by navigators to perform navigation tasks. All navigational techniques involve locating the navigator's position compared to known locations or patterns. Navigation, in a broader sense, can refer to any skill or study that involves the determination of position and direction. In this sense, navigation includes pedestrian navigation. In the European medieval period, navigation was considered part of the set of seven mechanical arts, none of which were used for long voyages across open ocean. Polynesian navigation is the earliest form of open-ocean navigation, it was based on memory and observation recorded on scientific instruments like the Marshall Islands Stick Charts of Ocean Swells.
Early Pacific Polynesians used the motion of stars, the position of certain wildlife species, or the size of waves to find the path from one island to another. Maritime navigation using scientific instruments such as the mariner's astrolabe first occurred in the Mediterranean during the Middle Ages. Although land astrolabes were invented in the Hellenistic period and existed in classical antiquity and the Islamic Golden Age, the oldest record of a sea astrolabe is that of Majorcan astronomer Ramon Llull dating from 1295; the perfecting of this navigation instrument is attributed to Portuguese navigators during early Portuguese discoveries in the Age of Discovery. The earliest known description of how to make and use a sea astrolabe comes from Spanish cosmographer Martín Cortés de Albacar's Arte de Navegar published in 1551, based on the principle of the archipendulum used in constructing the Egyptian pyramids. Open-seas navigation using the astrolabe and the compass started during the Age of Discovery in the 15th century.
The Portuguese began systematically exploring the Atlantic coast of Africa from 1418, under the sponsorship of Prince Henry. In 1488 Bartolomeu Dias reached the Indian Ocean by this route. In 1492 the Spanish monarchs funded Christopher Columbus's expedition to sail west to reach the Indies by crossing the Atlantic, which resulted in the Discovery of the Americas. In 1498, a Portuguese expedition commanded by Vasco da Gama reached India by sailing around Africa, opening up direct trade with Asia. Soon, the Portuguese sailed further eastward, to the Spice Islands in 1512, landing in China one year later; the first circumnavigation of the earth was completed in 1522 with the Magellan-Elcano expedition, a Spanish voyage of discovery led by Portuguese explorer Ferdinand Magellan and completed by Spanish navigator Juan Sebastián Elcano after the former's death in the Philippines in 1521. The fleet of seven ships sailed from Sanlúcar de Barrameda in Southern Spain in 1519, crossed the Atlantic Ocean and after several stopovers rounded the southern tip of South America.
Some ships were lost, but the remaining fleet continued across the Pacific making a number of discoveries including Guam and the Philippines. By only two galleons were left from the original seven; the Victoria led by Elcano sailed across the Indian Ocean and north along the coast of Africa, to arrive in Spain in 1522, three years after its departure. The Trinidad sailed east from the Philippines, trying to find a maritime path back to the Americas, but was unsuccessful; the eastward route across the Pacific known as the tornaviaje was only discovered forty years when Spanish cosmographer Andrés de Urdaneta sailed from the Philippines, north to parallel 39°, hit the eastward Kuroshio Current which took its galleon across the Pacific. He arrived in Acapulco on October 8, 1565; the term stems from the 1530s, from Latin navigationem, from navigatus, pp. of navigare "to sail, sail over, go by sea, steer a ship," from navis "ship" and the root of agere "to drive". The latitude of a place on Earth is its angular distance north or south of the equator.
Latitude is expressed in degrees ranging from 0° at the Equator to 90° at the North and South poles. The latitude of the North Pole is 90° N, the latitude of the South Pole is 90° S. Mariners calculated latitude in the Northern Hemisphere by sighting the North Star Polaris with a sextant and using sight reduction tables to correct for height of eye and atmospheric refraction; the height of Polaris in degrees above the horizon is the latitude of the observer, within a degree or so. Similar to latitude, the longitude of a place on Earth is the angular distance east or west of the prime meridian or Greenwich meridian. Longitude is expressed in degrees ranging from 0° at the Greenwich meridian to 180° east and west. Sydney, for example, has a longitude of about 151° east. New York City has a longitude of 74° west. For most of history, mariners struggled to determine longitude. Longitude can be calculated. Lacking that, one can use a sextant to take a lunar distance that, with a nautical almanac, can be used to calculate the time at zero longitude.
Reliable marine chronometers were unavailable until the late 18th century and not affordable until the 19th century. For about a hundred years, from about 1767 until about 1850, mariners lacking a chronometer used the method of lunar distances to determine Greenwich time to find their longitude. A mariner with a chronometer could check its reading using a lunar determination of Greenwich tim
Greenwich is an area of southeast London, located 5.5 miles east-southeast of Charing Cross. It is located within the Royal Borough of Greenwich. Greenwich is notable for its maritime history and for giving its name to the Greenwich Meridian and Greenwich Mean Time; the town became the site of a royal palace, the Palace of Placentia from the 15th century, was the birthplace of many Tudors, including Henry VIII and Elizabeth I. The palace fell into disrepair during the English Civil War and was rebuilt as the Royal Naval Hospital for Sailors by Sir Christopher Wren and his assistant Nicholas Hawksmoor; these buildings became the Royal Naval College in 1873, they remained an establishment for military education until 1998 when they passed into the hands of the Greenwich Foundation. The historic rooms within these buildings remain open to the public; the town became a popular resort in the 18th century and many grand houses were built there, such as Vanbrugh Castle established on Maze Hill, next to the park.
From the Georgian period estates of houses were constructed above the town centre. The maritime connections of Greenwich were celebrated in the 20th century, with the siting of the Cutty Sark and Gipsy Moth IV next to the river front, the National Maritime Museum in the former buildings of the Royal Hospital School in 1934. Greenwich formed part of Kent until 1889; the place-name ` Greenwich' is first attested in a Saxon charter of 918. It is recorded as Grenewic in 964, as Grenawic in the Anglo-Saxon Chronicle for 1013, it is Grenviz in the Domesday Book of 1086, Grenewych in the Taxatio Ecclesiastica of 1291. The name means'green wic or settlement'; the settlement became known as East Greenwich to distinguish it from West Greenwich or Deptford Strond, the part of Deptford adjacent to the Thames, but the use of East Greenwich to mean the whole of the town of Greenwich died out in the 19th century. However, Greenwich was divided into the registration subdistricts of Greenwich East and Greenwich West from the beginning of civil registration in 1837, the boundary running down what is now Greenwich Church Street and Crooms Hill, although more modern references to "East" and "West" Greenwich refer to the areas east and west of the Royal Naval College and National Maritime Museum corresponding with the West Greenwich council ward.
An article in The Times of 13 October 1967 stated: East Greenwich, gateway to the Blackwall Tunnel, remains solidly working class, the manpower for one eighth of London's heavy industry. West Greenwich is a hybrid: the spirit of Nelson, the Cutty Sark, the Maritime Museum, an industrial waterfront and a number of elegant houses, ripe for development. Royal charters granted to English colonists in North America used the name of the manor of East Greenwich for describing the tenure as that of free socage. New England charters provided that the grantees should hold their lands "as of his Majesty's manor of East Greenwich." This was in relation to the principle of land tenure under English law, that the ruling monarch was paramount lord of all the soil in the terra regis, while all others held their lands, directly or indirectly, under the monarch. Land outside the physical boundaries of England, as in America, was treated as belonging constructively to one of the existing royal manors, from Tudor times grants used the name of the manor of East Greenwich, but some 17c.
Grants named the castle of Windsor. Places in North America that have taken the name "East Greenwich" include a township in Gloucester County, New Jersey, a hamlet in Washington County, New York, a town in Kent County, Rhode Island. Greenwich, Connecticut was named after Greenwich. Tumuli to the south-west of Flamsteed House, in Greenwich Park, are thought to be early Bronze Age barrows re-used by the Saxons in the 6th century as burial grounds. To the east between the Vanbrugh and Maze Hill Gates is the site of a Roman temple. A small area of red paving tesserae protected by railings marks the spot, it was excavated in 1902 and 300 coins were found dating from the emperors Claudius and Honorius to the 5th century. This was excavated by the Channel 4 television programme Time Team in 1999, broadcast in 2000, further investigations were made by the same group in 2003; the Roman road from London to Dover, Watling Street crossed the high ground to the south of Greenwich, through Blackheath. This followed the line of an earlier Celtic route from Canterbury to St Albans.
As late as Henry V, Greenwich was only a fishing town, with a safe anchorage in the river. During the reign of Ethelred the Unready, the Danish fleet anchored in the River Thames off Greenwich for over three years, with the army being encamped on the hill above. From here they attacked Kent and, in the year 1012, took the city of Canterbury, making Archbishop Alphege their prisoner for seven months in their camp at Greenwich, at that time within the county of Kent, they stoned him to death for his refusal to allow his ransom to be paid. For this miracle his body was released to his followers, he achieved sainthood for his martyrdom and, in the 12th century, the parish church was dedicated to him; the present church on the site west of the town centre is St Alfege's Church, designed by Nicholas Hawksmoor in 1714 and completed in 1718. Some vestiges of the Danish camps may be traced in the nam