Vitis is a genus of 79 accepted species of vining plants in the flowering plant family Vitaceae. The genus is made up of species predominantly from the Northern hemisphere, it is economically important as the source of grapes, both for direct consumption of the fruit and for fermentation to produce wine. The study and cultivation of grapevines is called viticulture. Most Vitis varieties are wind-pollinated with hermaphroditic flowers containing both male and female reproductive structures; these flowers are grouped in bunches called inflorescences. In many species, such as Vitis vinifera, each pollinated flower becomes a grape berry with the inflorescence turning into a cluster of grapes. While the flowers of the grapevines are very small, the berries are big and brightly colored with sweet flavors that attract birds and other animals to disperse the seeds contained within the berries. Grapevines only produce fruit on shoots that came from buds that were developed during the previous growing season.
In viticulture, this is one of the principles behind pruning the previous year's growth that includes shoots that have turned hard and woody during the winter. These vines will be pruned either into a cane which will support 8 to 15 buds or to a smaller spur which holds 2 to 3 buds. Flower buds are formed late in the growing season and overwinter for blooming in spring of the next year, they produce leaf-opposed cymes. Vitis is distinguished from other genera of Vitaceae by having petals which remain joined at the tip and detach from the base to fall together as a calyptra or'cap'; the flowers are bisexual, with a hypogynous disk. The calyx is reduced or nonexistent in most species and the petals are joined together at the tip into one unit but separated at the base; the fruit is a berry, ovoid in shape and juicy, with a two-celled ovary each containing two ovules, thus producing four seeds per flower. Other parts of the vine include the tendrils which are leaf-opposed, branched in Vitis vinifera, are used to support the climbing plant by twining onto surrounding structures such as branches or the trellising of a vine-training system.
In the wild, all species of Vitis are dioecious, but under domestication, variants with perfect flowers appear to have been selected. Most Vitis species have but 40 in Vitis rotundifolia. Most Vitis species are found in the temperate regions of the Northern Hemisphere in North America and Asia with a few in the tropics; the wine grape Vitis vinifera originated in southern southwestern Asia. The species occur in different geographical areas and show a great diversity of form, their growth makes leaf collection challenging and polymorphic leaves make identification of species difficult. Mature grapevines can grow up to 48 cm in diameter at breast height and reach the upper canopy of trees more than 35 m in height. Many species are sufficiently related to allow easy interbreeding and the resultant interspecific hybrids are invariably fertile and vigorous, thus the concept of a species is less well defined and more represents the identification of different ecotypes of Vitis that have evolved in distinct geographical and environmental circumstances.
The exact number of species is not certain, with species in Asia in particular being poorly defined. Estimates range from 40 to more than 60; some of the more notable include: Vitis vinifera, the European grapevine. Native to the Mediterranean and Central Asia. Vitis labrusca, the fox grapevine, sometimes used for wine. Native to the Eastern United States and Canada. Vitis riparia, the riverbank grapevine, sometimes used for jam. Native to the entire Eastern U. S. and north to Quebec. Vitis aestivalis, the summer grape, native to the Eastern United States the Southeastern United States. Vitis rotundifolia, the muscadine, used for jams and wine. Native to the Southeastern United States from Delaware to the Gulf of Mexico. Vitis rupestris, the rock grapevine, used for breeding of Phylloxera resistant rootstock. Native to the Southern United States. Vitis coignetiae, the crimson glory vine, a species from East Asia grown as an ornamental plant for its crimson autumn foliage. Vitis amurensis, native to the Asian continent, including parts of China.
Vitis vulpina, the frost grape, native to the Eastern United States, from Massachusetts to Florida, west to Nebraska and Texas. Treated by some as a synonym of V. riparia. Vitis californica, the California wild grape, or Northern California grape, or Pacific grape, is a wild grape species widespread across much of California as well as southwestern Oregon. There are many cultivars of grapevines. Hybrid grapes exist, these are crosses between V. vinifera and one or more of V. labrusca, V. riparia or V. aestivalis. Hybrids tend to be less susceptible to frost and disease, but wine from some hybrids may have a little of the characteristic "foxy" taste of V. labrusca. The Latin word Vitis has feminine grammatical gender, therefore species names with adjectival specific epithets take feminine forms, such as V. vinifera. The fruit of several Vitis species are grown commercially for consumption as fresh grapes and for fermentation into wine. Vitis vinifera is the most important such species; the leaves of several species of grapevine are edible and are used in the production of dolmades and Vietnamese lot leaves.
According to the "Food and Agriculture Organization", 75,866 square kilometres of the world is dedicated to grapes. Approximate
Ancient Greek units of measurement
Ancient Greek units of measurement varied according to location and epoch. Systems of ancient weights and measures evolved; some units of measurement were found to be convenient for trade within the Mediterranean region and these units became common to different city states. The calibration and use of measuring devices became more sophisticated. By about 500 BC, Athens had a central depository of official weights and measures, the Tholos, where merchants were required to test their measuring devices against official standards; some Greek measures of length were named after parts of the body, such as the δάκτυλος or finger, the πούς or foot. The values of the units varied according to location and epoch, but the relative proportions were the same; the ordinary units used for land measurement were: Greeks measured volume according to either dry or liquid capacity, suited to measuring grain and wine. A common unit in both measures throughout historic Greece was the cotyle or cotyla whose absolute value varied from one place to another between 210 ml and 330 ml.
The basic unit for both solid and liquid measures was the κύαθος. The Attic liquid measures were: and the Attic dry measures of capacity were: The basic unit of Athenian currency was the obol, weighing 0.72 grams of silver: Weights are associated with currency since units of currency involve prescribed amounts of a given metal. Thus for example the English pound has been both a unit of currency. Greek weights bear a nominal resemblance to Greek currency yet the origin of the Greek standards of weights is disputed. There were two dominant standards of weight in the eastern Mediterranean: a standard that originated in Euboea and, subsequently introduced to Attica by Solon, a standard that originated in Aegina; the Attic/Euboean standard was based on the barley corn, of which there were twelve to one obol. However, weights that have been retrieved by historians and archeologists show considerable variations from theoretical standards. A table of standards derived from theory is as follows: Athenians measured the day by sundials and unit fractions.
Periods during night or day were measured by a water clock that dripped at a steady rate and other methods. Whereas the day in the Gregorian calendar commences after midnight, the Greek day began after sunset. Athenians named each year after the Archon Eponymos for that year, in Hellenistic times years were reckoned in quadrennial epochs according to the Olympiad. In archaic and early classical Greece, months followed the cycle of the Moon which made them not fit into the length of the solar year. Thus, if not corrected, the same month would migrate into different seasons of the year; the Athenian year was divided into 12 months, with one additional month being inserted between the sixth and seventh months every second year. With this intercalary month, the Athenian or Attic calendar was still inaccurate and days had to be added by the Archon Basileus; the start of the year was at the summer solstice and months were named after Athenian religious festivals, 27 mentioned in the Hibah Papyrus, circ 275 BC. Roman units Byzantine units Stadia rod "History 310: Greek Coinage and Measures".
History/Classics 310. Archived from the original on April 8, 2005. Retrieved December 15, 2005. Porter, John. "Greek and Roman Weights and Currency". Archived from the original on 6 August 2007. Retrieved July 26, 2007. Online Conversion of Ancient Greek Units
Measurement is the assignment of a number to a characteristic of an object or event, which can be compared with other objects or events. The scope and application of measurement are dependent on the discipline. In the natural sciences and engineering, measurements do not apply to nominal properties of objects or events, consistent with the guidelines of the International vocabulary of metrology published by the International Bureau of Weights and Measures. However, in other fields such as statistics as well as the social and behavioral sciences, measurements can have multiple levels, which would include nominal, ordinal and ratio scales. Measurement is a cornerstone of trade, science and quantitative research in many disciplines. Many measurement systems existed for the varied fields of human existence to facilitate comparisons in these fields; these were achieved by local agreements between trading partners or collaborators. Since the 18th century, developments progressed towards unifying accepted standards that resulted in the modern International System of Units.
This system reduces all physical measurements to a mathematical combination of seven base units. The science of measurement is pursued in the field of metrology; the measurement of a property may be categorized by the following criteria: type, magnitude and uncertainty. They enable unambiguous comparisons between measurements; the level of measurement is a taxonomy for the methodological character of a comparison. For example, two states of a property may be compared by difference, or ordinal preference; the type is not explicitly expressed, but implicit in the definition of a measurement procedure. The magnitude is the numerical value of the characterization obtained with a suitably chosen measuring instrument. A unit assigns a mathematical weighting factor to the magnitude, derived as a ratio to the property of an artifact used as standard or a natural physical quantity. An uncertainty represents the systemic errors of the measurement procedure. Errors are evaluated by methodically repeating measurements and considering the accuracy and precision of the measuring instrument.
Measurements most use the International System of Units as a comparison framework. The system defines seven fundamental units: kilogram, candela, ampere and mole. Six of these units are defined without reference to a particular physical object which serves as a standard, while the kilogram is still embodied in an artifact which rests at the headquarters of the International Bureau of Weights and Measures in Sèvres near Paris. Artifact-free definitions fix measurements at an exact value related to a physical constant or other invariable phenomena in nature, in contrast to standard artifacts which are subject to deterioration or destruction. Instead, the measurement unit can only change through increased accuracy in determining the value of the constant it is tied to; the first proposal to tie an SI base unit to an experimental standard independent of fiat was by Charles Sanders Peirce, who proposed to define the metre in terms of the wavelength of a spectral line. This directly influenced the Michelson–Morley experiment.
With the exception of a few fundamental quantum constants, units of measurement are derived from historical agreements. Nothing inherent in nature dictates that an inch has to be a certain length, nor that a mile is a better measure of distance than a kilometre. Over the course of human history, first for convenience and for necessity, standards of measurement evolved so that communities would have certain common benchmarks. Laws regulating measurement were developed to prevent fraud in commerce. Units of measurement are defined on a scientific basis, overseen by governmental or independent agencies, established in international treaties, pre-eminent of, the General Conference on Weights and Measures, established in 1875 by the Metre Convention, overseeing the International System of Units and having custody of the International Prototype Kilogram; the metre, for example, was redefined in 1983 by the CGPM in terms of light speed, while in 1960 the international yard was defined by the governments of the United States, United Kingdom and South Africa as being 0.9144 metres.
In the United States, the National Institute of Standards and Technology, a division of the United States Department of Commerce, regulates commercial measurements. In the United Kingdom, the role is performed by the National Physical Laboratory, in Australia by the National Measurement Institute, in South Africa by the Council for Scientific and Industrial Research and in India the National Physical Laboratory of India. Before SI units were adopted around the world, the British systems of English units and imperial units were used in Britain, the Commonwealth and the United States; the system came to be known as U. S. is still in use there and in a few Caribbean countries. These various systems of measurement have at times been called foot-pound-second systems after the Imperial units for length and time though the tons, hundredweights and nautical miles, for example, are different for the U. S. units. Many Imperial units remain in use in Britain, which has switched to the SI system—with a few exceptions such as road signs, which are still in miles.
Draught beer and cider must be sold by the imperial pint, milk in returnable bottles can be sold by the imperial pint. Many people meas
Ancient Egyptian units of measurement
The ancient Egyptian units of measurement are those used by the dynasties of ancient Egypt prior to its incorporation in the Roman Empire and general adoption of Roman and Byzantine units of measurement. The units of length seem to have been anthropic, based on various parts of the human body, although these were standardized using cubit rods, strands of rope, official measures maintained at some temples. Following Alexander the Great's conquest of Persia and subsequent death, his bodyguard and successor Ptolemy assumed control in Egypt reforming its measurements, introducing some new units and hellenized names for others. Egyptian units of length are attested from the Early Dynastic Period. Although it dates to the 5th dynasty, the Palermo stone recorded the level of the Nile River during the reign of the Early Dynastic pharaoh Djer, when the height of the Nile was recorded as 6 cubits and 1 palm. A 3rd-dynasty diagram shows; the ostracon depicting this diagram was found near the Step Pyramid of Saqqara.
A curve is divided into five sections and the height of the curve is given in cubits and digits in each of the sections. At some point, lengths were standardized by cubit rods. Examples have been found in the tombs of officials. Royal cubits were used for land measures such as fields. Fourteen rods, including one double-cubit rod, were compared by Lepsius. Two examples are known from the Saqqara tomb of the treasurer of Tutankhamun. Another was found in the tomb of Kha in Thebes; these cubits are about 52.5 cm long and are divided into palms and hands: each palm is divided into four fingers from left to right and the fingers are further subdivided into ro from right to left. The rules are divided into hands so that for example one foot is given as three hands and fifteen fingers and as four palms and sixteen fingers. Surveying and itinerant measurement were undertaken using rods and knotted cords of rope. A scene in the tomb of Menna in Thebes shows surveyors measuring a plot of land using rope with knots tied at regular intervals.
Similar scenes can be found in the tombs of Amenhotep-Sesi and Djeserkareseneb. The balls of rope are shown in New Kingdom statues of officials such as Senenmut, Amenemhet-Surer, Penanhor; the digit was subdivided into smaller fractions of ½, ⅓, ¼, 1⁄16. Minor units include the Middle Kingdom reed of 2 royal cubits, the Ptolemaic xylon of three royal cubits, the Ptolemaic fathom of four lesser cubits, the kalamos of six royal cubits. Records of land area date to the Early Dynastic Period; the Palermo stone records grants of land expressed in terms of setat. Mathematical papyri include units of land area in their problems. For example, several problems in the Moscow Mathematical Papyrus give the area of rectangular plots of land in terms of setat and the ratio of the sides and require the scribe to solve for their exact lengths; the setat was the basic unit of land measure and may have varied in size across Egypt's nomes. It was equal to one square khet, where a khet measured 100 cubits; the setat could be divided into strips one khet long and ten cubit wide.
During the Old Kingdom: During the Middle and New Kingdom, the "eighth", "fourth", "half", "thousand" units were taken to refer to the setat rather than the cubit strip: During the Ptolemaic period, the cubit strip square was surveyed using a length of 96 cubits rather than 100, although the aroura was still figured to compose 2756.25 m². A 36 sq. cubit area was known as a 144 sq. cubit area as a hamma. The uncommon bikos may have been another name for the cubit strip; the Coptic shipa was a land unit of uncertain value derived from Nubia. Units of volume appear in the mathematical papyri. For example, computing the volume of a circular granary in RMP 42 involves cubic cubits, khar and quadruple heqats. RMP 80 divides heqats of grain into smaller henu; the oipe was formerly romanized as the apet. Weights were measured in terms of deben; this unit would have been equivalent to 13.6 grams in the Old Middle Kingdom. During the New Kingdom however it was equivalent to 91 grams. For smaller amounts the qedet and the shematy were used.
The qedet or kedet is often known as the kite, from the Coptic form of the same name. In 19th-century sources, the deben and qedet are mistakenly transliterated as the uten and kat although this was corrected by the 20th century; the former annual flooding of the Nile organized prehistoric and ancient Egypt into three seasons: Akhet and Shemu or Shomu. The Egyptian civil calendar in place by Dynasty V followed regnal eras resetting with the ascension of each new pharaoh, it was based on the solar year and initiated during a heliacal rising of Sirius following a recognition of its rough correlation with the onset of the Nile flood. It followed none of these however, its year was divided into 3 seasons, 12 months, 36 decans, or 360 days with another 5 epagomenal days—celebrated as the birthdays of five major gods but feared for their ill luck—added "upon the year". The Egyptian months were simply numbered within each season but, in sources, they acquired names from the year's major festivals and the three decans of each one were distinguished as "first", "middle", "last".
It has been suggested that during the Nineteenth Dynasty
The mile is an English unit of length of linear measure equal to 5,280 feet, or 1,760 yards, standardised as 1,609.344 metres by international agreement in 1959. With qualifiers, "mile" is used to describe or translate a wide range of units derived from or equivalent to the Roman mile, such as the nautical mile, the Italian mile, the Chinese mile; the Romans divided their mile into 5,000 roman feet but the greater importance of furlongs in pre-modern England meant that the statute mile was made equivalent to 8 furlongs or 5,280 feet in 1593. This form of the mile spread to the British-colonized nations some of which continue to employ the mile; the US Geological Survey now employs the metre for official purposes but legacy data from its 1927 geodetic datum has meant that a separate US survey mile continues to see some use. While most countries replaced the mile with the kilometre when switching to the International System of Units, the international mile continues to be used in some countries, such as Liberia, the United Kingdom, the United States, a number of countries with fewer than one million inhabitants, most of which are UK or US territories, or have close historical ties with the UK or US.
The mile was abbreviated m. in the past but is now sometimes written as mi to avoid confusion with the SI metre. However, derived units, such as miles per hour or miles per gallon, continue to be universally abbreviated as mph and mpg, respectively; the modern English word mile derives from Middle English myl and Old English mīl, cognate with all other Germanic terms for "miles". These derived from apocopated forms of the Latin mīlia or mīllia, the plural of mīle or mīlle "thousand" but used as a clipped form of mīlle passus or passuum, the Roman mile of one thousand paces; the present international mile is what is understood by the unqualified term "mile". When this distance needs to be distinguished from the nautical mile, the international mile may be described as a "land mile" or "statute mile". In British English, the "statute mile" may refer to the present international miles or to any other form of English mile since the 1593 Act of Parliament, which set it as a distance of 1,760 yards.
Under American law, the "statute mile" refers to the US survey mile. Foreign and historical units translated into English as miles employ a qualifier to describe the kind of mile being used but this may be omitted if it is obvious from the context, such as a discussion of the 2nd-century Antonine Itinerary describing its distances in terms of "miles" rather than "Roman miles"; the mile has been variously abbreviated—with and without a trailing period—as m, M, ml, mi. The American National Institute of Standards and Technology now uses and recommends mi in order to avoid confusion with the SI metre and millilitre. However, derived units such as miles per hour or miles per gallon continue to be abbreviated as mph and mpg rather than mi/h and mi/gal. In the United Kingdom road signs use m as the abbreviation for mile though height and width restrictions use m as the abbreviation for the metre, which may be displayed alongside feet and inches; the BBC style holds that "There is no acceptable abbreviation for'miles'" and so it should be spelt out when used in describing areas.
The Roman mile consisted of a thousand paces as measured by every other step—as in the total distance of the left foot hitting the ground 1,000 times. The ancient Romans, marching their armies through uncharted territory, would push a carved stick in the ground after each 1,000 paces. Well-fed and harshly driven Roman legionaries in good weather thus created longer miles; the distance was indirectly standardised by Agrippa's establishment of a standard Roman foot in 29 BC, the definition of a pace as 5 feet. An Imperial Roman mile thus denoted 5,000 Roman feet. Surveyors and specialized equipment such as the decempeda and dioptra spread its use. In modern times, Agrippa's Imperial Roman mile was empirically estimated to have been about 1,617 yards in length. In Hellenic areas of the Empire, the Roman mile was used beside the native Greek units as equivalent to 8 stadia of 600 Greek feet; the mílion continued to be used as a Byzantine unit and was used as the name of the zero mile marker for the Byzantine Empire, the Milion, located at the head of the Mese near Hagia Sophia.
The Roman mile spread throughout Europe, with its local variations giving rise to the different units below. Arising from the Roman mile is the "milestone". All roads radiated out from the Roman Forum throughout the Empire – 50,000 miles of stone-paved roads. At every mile was placed a shaped stone, on, carved a Roman numeral, indicating the number of miles from the center of Rome – the Forum. Hence, one always knew; the Italian mile was traditionally considered a direct continuation of the Roman mile, equal to 1000 paces, although its actual value over time or between regions could vary greatly. It was used in international contexts from the Middle Ages into the 17th century and is thus known as the "geographical mile", although the geographical mile is now a separate standard unit; the Arabic mile was not the common Arabic unit of length. The Arabic mile was, used by medieval geographers and scientists and constituted a kind of precursor to the nautical or geographical mile, it extended the Roman mile to fit an astronomical approximatio
Egyptian hieroglyphs were the formal writing system used in Ancient Egypt. Hieroglyphs combined logographic and alphabetic elements, with a total of some 1,000 distinct characters. Cursive hieroglyphs were used for religious literature on papyrus and wood; the hieratic and demotic Egyptian scripts were derived from hieroglyphic writing, as was the Proto-Siniatic script that evolved into the Phoenician alphabet. Through the Phoenician alphabet's major child systems, the Greek and Aramaic scripts, the Egyptian hieroglyphic script is ancestral to the majority of scripts in modern use, most prominently the Latin and Cyrillic scripts and the Arabic script and Brahmic family of scripts; the use of hieroglyphic writing arose from proto-literate symbol systems in the Early Bronze Age, around the 32nd century BC, with the first decipherable sentence written in the Egyptian language dating to the Second Dynasty. Egyptian hieroglyphs developed into a mature writing system used for monumental inscription in the classical language of the Middle Kingdom period.
The use of this writing system continued through the New Kingdom and Late Period, on into the Persian and Ptolemaic periods. Late survivals of hieroglyphic use are found well into the Roman period, extending into the 4th century AD. With the final closing of pagan temples in the 5th century, knowledge of hieroglyphic writing was lost. Although attempts were made, the script remained undeciphered throughout the Middle Ages and the early modern period; the decipherment of hieroglyphic writing would only be accomplished in the 1820s by Jean-François Champollion, with the help of the Rosetta Stone. The word hieroglyph comes from the Greek adjective ἱερογλυφικός, a compound of ἱερός and γλύφω; the glyphs themselves since the Ptolemaic period were called τὰ ἱερογλυφικὰ "the sacred engraved letters", the Greek counterpart to the Egyptian expression of mdw.w-nṯr "god's words". Greek ἱερογλυφός meant "a carver of hieroglyphs". In English, hieroglyph as a noun is recorded from 1590 short for nominalised hieroglyphic, from adjectival use.
Hieroglyphs may have emerged from the preliterate artistic traditions of Egypt. For example, symbols on Gerzean pottery from c. 4000 BC have been argued to resemble hieroglyphic writing. Proto-hieroglyphic symbol systems develop in the second half of the 4th millennium BC, such as the clay labels of a Predynastic ruler called "Scorpion I" recovered at Abydos in 1998 or the Narmer Palette; the first full sentence written in mature hieroglyphs so far discovered was found on a seal impression found in the tomb of Seth-Peribsen at Umm el-Qa'ab, which dates from the Second Dynasty. There are around 800 hieroglyphs dating back to the Old Kingdom, Middle Kingdom and New Kingdom Eras. By the Greco-Roman period, there are more than 5,000. Geoffrey Sampson stated that Egyptian hieroglyphs "came into existence a little after Sumerian script, invented under the influence of the latter", that it is "probable that the general idea of expressing words of a language in writing was brought to Egypt from Sumerian Mesopotamia".
There are many instances of early Egypt-Mesopotamia relations, but given the lack of direct evidence for the transfer of writing, "no definitive determination has been made as to the origin of hieroglyphics in ancient Egypt". Instead, it is pointed out and held that "the evidence for such direct influence remains flimsy” and that “a credible argument can be made for the independent development of writing in Egypt..." Since the 1990s, the discoveries of glyphs at Abydos, dated to between 3400 and 3200 BCE, may challenge the classical notion according to which the Mesopotamian symbol system predates the Egyptian one, although Egyptian writing does make a sudden apparition at that time, while on the contrary Mesopotamia has an evolutionnary history of sign usage in tokens dating back to circa 8000 BCE. Hieroglyphs consist of three kinds of glyphs: phonetic glyphs, including single-consonant characters that function like an alphabet; as writing developed and became more widespread among the Egyptian people, simplified glyph forms developed, resulting in the hieratic and demotic scripts.
These variants were more suited than hieroglyphs for use on papyrus. Hieroglyphic writing was not, eclipsed, but existed alongside the other forms in monumental and other formal writing; the Rosetta Stone contains three parallel scripts – hieroglyphic and Greek. Hieroglyphs continued to be used under Persian rule, after Alexander the Great's conquest of Egypt, during the ensuing Ptolemaic and Roman periods, it appears that the misleading quality of comments from Greek and Roman writers about hieroglyphs came about, at least in part, as a response to the changed political situation. Some believed that hieroglyphs may have functioned as a way to distinguish'true Egyptians' from some of the foreign conquerors. Another reason may be the refusal to tackle a foreign culture on its own terms, which characterized Greco-Roman approaches to Egyptian culture generally. Having learned that hieroglyphs were sacred writing, Greco-Roman authors imagined the complex but rational system as an allegorical magical, system transmitting secre
Nubia is a region along the Nile river encompassing the area between Aswan in southern Egypt and Khartoum in central Sudan. It was the seat of one of the earliest civilizations of ancient Africa, with a history that can be traced from at least 2500 BC onward with the Kerma culture; the latter was conquered by the New Kingdom of Egypt under pharaoh Thutmose I around 1500 BC. Nubia was home to several empires, most prominently the kingdom of Kush, which conquered Egypt during the 8th century BC during the reign of Piye and ruled the country as its Twenty-fifth Dynasty; the collapse of Kush in the 4th century AD after more than a thousand years of existence was precipitated by an invasion by Ethiopia's Kingdom of Aksum and saw the rise of three Christian kingdoms, Nobatia and Alodia, the last two again lasting for a millennium. Their eventual decline initiated not only the partition of Nubia into the northern half conquered by the Ottomans and the southern half by the Sennar sultanate in the 16th century, but a rapid Islamization and partial Arabization of the Nubian people.
Nubia was again united with the Khedivate of Egypt in the 19th century. Today, the region of Nubia is split between Sudan; the archaeological science dealing with ancient Nubia is called Nubiology. The name Nubia is derived from that of the Noba people, nomads who settled the area in the 4th century CE following the collapse of the kingdom of Meroë; the Noba spoke a Nilo-Saharan language, ancestral to Old Nubian. Old Nubian was used in religious texts dating from the 8th and 15th centuries. Before the 4th century, throughout classical antiquity, Nubia was known as Kush, or, in Classical Greek usage, included under the name Ethiopia; the people of Nubia spoke at least two varieties of the Nubian language group, a subfamily that includes Nobiin, Kenuzi-Dongola and several related varieties in the northern part of the Nuba Mountains in South Kordofan. Until at least 1970, the Birgid language is now extinct. However, linguistic evidence indicates that the languages spoken in the ancient Kerma Culture in Nubia, belonged to the Cushitic branch of the Afroasiatic languages.
Nubia was divided into three major regions: Upper and Lower Nubia, in reference to their locations along the Nile. Lower refers to regions upper refers to regions upstream. Lower Nubia lies within the current borders of Egypt. Middle Nubia lies between the Third Cataracts. Upper Nubia lies south of the Third Cataract. Early settlements sprouted in both Lower Nubia. Egyptians referred to Nubia as "Ta-Seti," or "The Land of the Bow," since the Nubians were known to be expert archers. Modern scholars refer to the people from this area as the "A-Group" culture. Fertile farmland just south of the Third Cataract is known as the "pre-Kerma" culture in Upper Nubia, as they are the ancestors; the Neolithic people in the Nile Valley came from Sudan, as well as the Sahara, there was shared culture with the two areas and with that of Egypt during this period. By the 5th millennium BC, the people who inhabited what is now called Nubia participated in the Neolithic revolution. Saharan rock reliefs depict scenes that have been thought to be suggestive of a cattle cult, typical of those seen throughout parts of Eastern Africa and the Nile Valley to this day.
Megaliths discovered at Nabta Playa are early examples of what seems to be one of the world's first astronomical devices, predating Stonehenge by 2,000 years. This complexity as observed at Nabta Playa, as expressed by different levels of authority within the society there formed the basis for the structure of both the Neolithic society at Nabta and the Old Kingdom of Egypt. Around 3500 BC, the second "Nubian" culture, termed the A-Group, arose, it was a contemporary of, ethnically and culturally similar to, the polities in predynastic Naqada of Upper Egypt. The A-Group people were engaged in trade with the Egyptians; this trade is testified archaeologically by large amounts of Egyptian commodities deposited in the graves of the A-Group people. The imports consisted of gold objects, copper tools, faience amulets and beads, slate palettes, stone vessels, a variety of pots. Around 3300 BC, there is evidence of a unified kingdom, as shown by the finds at Qustul, that maintained substantial interactions with the culture of Naqadan Upper Egypt.
The Nubian culture may have contributed to the unification of the Nile Valley. Toby Wilkinson, based on work by Bruce Williams in the 1980s, wrote that "The white crown, associated in historic times with Upper Egypt, is first attested than the red crown, but is directly associated with the ruler somewhat earlier; the earliest known depiction of the white crown is on a ceremonial incense burner from Cemetery at Qustul in Lower Nubia". Based on a 1998 excavation report, Jane Roy has written that "At the time of Williams' argument, the Qustul cemetery and the'royal' iconography found there was dated to the Naqada IIIA period, thus antedating royal cemeteries in Egypt of the Naqada IIIB phase. New evidence from Abydos, however the excavation of Cemetery U and the tome U-j, dating to Naqada IIIA has shown that this iconography appears earlier in Egypt." Around the turn of the protodynastic period, Naqada, in its bid to conquer and unify the whole Nile Valley, seems to have conquered Ta-Seti and harmonized it with the Egyptian state.
Thus, Nubia became the first