Non-Euclidean geometry that are both perpendicular to a third line: Euclidean geometry, named after the Greek mathematician Euclid, includes some of the oldest known mathematics, and geometries that deviated from this were not widely accepted as legitimate until the 19th century. The debate that eventually led to the discovery of the non-Euclidean geometries began almost as soon as Euclid's work "Elements" was written. In the "Elements", Euclid began with a limited number of assumptions (23 definitions, five common notions, and five postulates) and sought to prove all the other results (propositions) in the work. The most notorious of the postulates is often
History of Alexandria wealth and power of the Ptolemies, but also celebrated and affirmed Greekness. These processions were used to shout Greek superiority over any non-Greeks that were watching, thereby widening the divide between cultures. From this division arose much of the later turbulence, which began to manifest itself under the rule of Ptolemy Philopater (221–204 BC). The reign of Ptolemy VIII Physcon from 144–116 BC was marked by purges and civil warfare (including the expulsion of intellectuals such as Apollodorus of Athens), as well as intrigues associated with the king's wives and sons. Alexandria was also home to the largest Jewish community