Much of the content of the Tetrabiblos was collected from earlier sources ; Ptolemy's achievement was to order his material in a systematic way, showing how the subject could, in his view, be rationalized.

I confirm this view not only by refuting Ptolemy's and Aristotle's arguments, but also by producing many for the other side, especially some pertaining to physical effects whose causes perhaps cannot be determined in any other way, and other astronomical discoveries ; these discoveries clearly confute the Ptolemaic system, and they agree admirably with this other position and confirm it.

A chorographer in Ptolemy's view was the expert in a specific locality, such as a ship captain, a merchant, or a native.

" This excerpt reflects Ptolemy's gnostic view that the god that created the world is not the Perfect God, but rather an inferior god who incorrectly believed that he was the one true God, which is what he is trying to convey to Flora.

This view resulted chiefly from the fact that they were not believed at the time to be made up of most of the historical septs mentioned above, but to belong mostly to the realm of later mytho-historical tradition and antiquarian speculation, and of course to Ptolemy's Geography.

Although authentic maps have never been found, the Geographia contains thousands of references to various parts of the old world, with coordinates for most, which allowed cartographers to reconstruct Ptolemy's world view when the manuscript was re-discovered around 1300 CE.

This is taken to demonstrate Ptolemy's view that astronomy and astrology are complementary studies, so that whilst astrology is less self-sufficient and factual, its employment makes the practice of astronomy more useful.

Historian Nicholas Campion has discussed the roots of the notion that celestial and psychological realms are connected, which can be traced to the sixth century BC, and in Ptolemy's case presents a mixture of Aristotelian and Stoic philosophy, resting on the Platonic view that " the soul comes from the heavens " which explains " how human character comes to be determined by the heavens ".

Ptolemy's view of the north is so distorted that his names require some decoding to locate them, nor can that be done with very great certainty.

In any case the population of the region must belong to Ptolemy's Tarabeni or Titiani people, neither of which are ever heard about again.

Ptolemy's Geography from the second century CE describes Sarakene as a region in the northern Sinai peninsula.

Christian and Muslim philosophers modified Ptolemy's system to include an unmoved outermost region, the empyrean heaven, which came to be identified as the dwelling place of God and all the elect.

There is a consensus among scholars that Ptolemy's Dacia was the region between the rivers Tisza, Danube, upper Dniester, and Siret.

The Dards and Chinas appear in many of the old Pauranic lists of peoples who lived in the region, with the former also mentioned in Ptolemy's accounts of the region.

They are probably the same as Ptolemy's Doulgoumnioi of the same region ( Book 2, Chapter 10 ), as Ptolemy corrupts the names of the other tribes, but identifiably so.

Ptolemy's two maps of Germany portrayed Germania Inferior on the left bank of the Rhine, which was populated by Germanics, including those who had occupied the region before the Romans, and Magna Germania on the other side of the river, which acted as the Roman frontier.

The Periplus of the Erythraean Sea ( 1st century ) and Ptolemy's Geographia ( 2nd century ) calls the region Kirrhadia after the Kirata population.

Islay is Ptolemy's Epidion, the use of the " p " hinting at a Brythonic or Pictish tribal name, although the root is not Gaelic and of unknown origin.

In the case of Ptolemy's Dacia, most of the tribal names are similar to those on the list of civitates, with few exceptions. Georgiev counts the Triballi, the Moesians and the Dardanians as Daco-Moesians.

Ptolemy's maps reflect generally the same tribal names as the Tabula Peutingeriana, except that the tabula does not mention the Sicambri.

George of Trebizond who was Bessarion's philosophical rival had recently produced a new Latin translation of Ptolemy's Almagest from the Greek, which Bessarion, correctly, regarded as inaccurate and badly translated, so he asked Peuerbach to produce a new one.

In 1802, Silvestre de Sacy reported to Chaptal that he had successfully identified five names (" Alexandros ", " Alexandreia ", " Ptolemaios ", " Arsinoe " and Ptolemy's title " Epiphanes "), while Åkerblad published an alphabet of 29 letters ( more than half of which were correct ) that he had identified from the Greek names in the demotic text.

Two hundred years after the construction of Ptolemy's canal, Cleopatra seems to have had no west-east waterway passage, because the Pelusiac branch of the Nile River, which had fed Ptolemy's west-east canal, had by that time dwindled, being choked with silt.

The serious errors which he found in previous Arabian star catalogues ( many of which had simply updated Ptolemy's work, adding the effect of precession to the longitudes ) induced him to redetermine the positions of 992 fixed stars, to which he added 27 stars from Abd al-Rahman al-Sufi's catalogue Book of Fixed Stars from the year 964, which were too far south for observation from Samarkand.

They had found the " Flat Mountain " of Ptolemy's Geography.

Ptolemy's maps, which became well known in Europe during the Renaissance, did not actually depict such a continent, but they did show an Africa which had no southern oceanic boundary ( and which therefore might extend all the way to the South Pole ), and also raised the possibility that the Indian Ocean was entirely enclosed by land.

One famous apocryphal quote attributed to him upon hearing an explanation of the extremely complicated mathematics required to demonstrate Ptolemy's theory of astronomy was " If the Lord Almighty had consulted me before embarking on creation thus, I should have recommended something simpler.

It may have had its origins with the Damnonii people of Ptolemy's Geographia.

As Trenčín is much further south than the latitude given by Ptolemy, this identification seems to imply that Ptolemy's data on latitude of places north of the Danube had significant errors, hence making the Calisia-Kalisz identification doubtful.

There he learned Arabic, initially, so that he could read Ptolemy's Almagest, which had a traditionally high reputation among scholars, but which, before his departure to Castile, was not yet known in Latin translation.

In the 16th century, Nicolaus Copernicus De revolutionibus presented a full discussion of a heliocentric model of the universe in much the same way as Ptolemy's Almagest had presented his geocentric model in the 2nd century.

In antiquity they were known as the Pityusa islands, listed in Claudius Ptolemy's Geography, under the names Ophiusis and Ebyssus, which had a town of the same name.

In the 16th century, Nicolaus Copernicus's De revolutionibus presented a full discussion of a heliocentric model of the universe in much the same way as Ptolemy's Almagest had presented his geocentric model in the 2nd century.

Bayer listed a dozen figures that had been suggested since Ptolemy's day ; Lacaille created new groups, mostly for the area near the South Celestial Pole, unobserved by the ancients.

By Ptolemy's day, Libra had become an independent constellation, unconnected with either of its neighbors.

The book, first printed in 1543 in Nuremberg, Holy Roman Empire of the German Nation, offered an alternative model of the universe to Ptolemy's geocentric system, which had been widely accepted since ancient times.

It was probably once the name given to all the peoples of Ireland, but by Ptolemy's time had a more restricted usage applicable to the inhabitants of the south-west.

( There is a famous ( but probably apocryphal ) quote attributed to Alfonso upon hearing an explanation of the extremely complicated mathematics required to demonstrate Ptolemy's geocentric model of the solar system: " If the Lord Almighty had consulted me before embarking on creation thus, I should have recommended something simpler.

It is likely that the destination was a Roman port now lost to coastal erosion, which has been tentatively identified with the ' Novus Portus ' mentioned in Ptolemy's Geographia.

Without any suitable island matching Ptolemy's Counus Island, it is also thought that the documented island has been lost or reduced to an insignificant sandbank by subsidence and the constant effects of the sea since Ptolemy's time.

There is little evidence on the subject of Ptolemy's ancestry, apart from what can be drawn from the details of his name ( see above ); however modern scholars refer to Abu Ma ’ shar ’ s account as erroneous, and it is no longer doubted that the astronomer who wrote the Almagest also wrote the Tetrabiblos as its astrological counterpart.

* 1150s – Gerard of Cremona translates Ptolemy's Almagest from Arabic into Latin, eventually leading to its adoption by the Catholic Church as an approved text.

Ne ' eman argued that after Gersonides reviewed Ptolemy's model with its epicycles he realized that it could be checked, by measuring the changes in the apparent brightnesses of Mars and looking for cyclical changes along the conjectured epicycles.

Levi also showed that Ptolemy's model for the Lunar orbit, though reproducing correctly the evolution of the Moon's position, fails completely in predicting the apparent sizes of the Moon in its motion.

Near the end of Ptolemy's reign, the value of Egyptian coins dropped to about fifty percent of its value at the beginning of his reign.

In Ptolemy's physical model, each planet is contained in two or more spheres, but in Book 2 of his Planetary Hypotheses Ptolemy depicted thick circular slices rather than spheres as in its Book 1.

The body of astrological knowledge by the 2nd century AD is described in Ptolemy's Tetrabiblos, a work that was responsible for astrology's successful spread across Europe and the Middle East, and remained a reference for almost seventeen centuries as later traditions made few substantial changes to its core teachings.

Hipparchus split it off in the 200s BC, and Ptolemy's list confirmed its independent status.

Steeped in history the lough and the Grianán Ailigh hill fort ( early fortification and palace dating from 2000-5000 BC ) at its southeastern bend was recorded on Ptolemy's map of the world.

If now diameter AF is drawn bisecting DC so that DF and CF are sides c of an inscribed decagon, Ptolemy's Theorem can again be applied – this time to cyclic quadrilateral ADFC with diameter d as one of its diagonals:

While the existence of China was clearly known to Roman cartographers of the time, its geographical position is depicted in Ptolemy's Geographia from c. 150 AD rather vaguely: On the map, China is located beyond the Aurea Chersonesus (" Golden Peninsula "), which refers to the Southeast Asian peninsula.

Ptolemy's Almagest was an authoritative text on astronomy for more than a thousand years, and the Tetrabiblos, its companion volume, was equally influential in astrology, the study of the effects of astronomical cycles on earthly matters.

Ptolemy's comments counter the criticism by proposing that whilst the celestial cycles are entirely reliable and " eternally performed in accordance with divine, unchangeable destiny ", all earthly things are also subject to " a natural and mutable fate, and in drawing its first causes from above it is governed by chance and natural sequence ".

Ptolemy's philosophical conclusion on the subject, which helped to secure its intellectual standing until the 18th century, is thus: " even if it be not entirely infallible, at least its possibilities have appeared worthy of the highest regard ".

Chapter 2, on material wealth, employs the " so-called ' Lot of Fortune '" although Ptolemy's instruction conflicts with that of many of his contemporaries in stating that for its calculation " we measure from the horoscope the distance from the sun to the moon, in both diurnal and nocturnal nativities ".