Foundations of geometry possible exception of the parallel postulate) that any theorem proved from them was deemed true in an absolute, often metaphysical, sense. Today, however, many other geometries which are not Euclidean are known, the first ones having been discovered in the early 19th century. Euclid's "Elements" is a mathematical and geometric treatise consisting of 13 books written by the ancient Greek mathematician Euclid in Alexandria c. 300 BC. It is a collection of definitions, postulates (axioms), propositions (theorems and constructions), and mathematical proofs of the propositions. The thirteen books cover Euclidean geometry and the ancient Greek version of elementary number theory.
Ptolemy II Philadelphus and dissolute, intellectual and artificial, has been compared with the Palace of Versailles of Louis XIV of France. Ptolemy deified his parents and his sister-wife after their deaths. Ptolemy II began his reign as co-regent with his father, Ptolemy Soter, from c. 285 to c. 283 BCE, and maintained a splendid court in Alexandria. Egypt was involved in several wars during his reign. His maternal half-brother Magas had declared himself king of Cyrene in 276 and began a war against Ptolemy's government in 274 BCE. Magas managed to keep Cyrenaica independent of the Ptolemies until his death in 250 BCE.