Euclid's Elements Euclid's Elements The Elements ( "Stoicheia") is a mathematical treatise consisting of 13 books attributed to the ancient Greek mathematician Euclid in Alexandria, Ptolemaic Egypt c. 300 BC. It is a collection of definitions, postulates, propositions (theorems and constructions), and mathematical proofs of the propositions. The books cover plane and solid Euclidean geometry, elementary number theory, and incommensurable lines. "Elements" is the oldest extant large-scale deductive treatment of mathematics. It has proven instrumental in the development of logic and modern science, and its logical rigor was not surpassed until the 19th century. Euclid's "Elements" has been referred to as the
Ptolemy I Soter Ptolemy I Soter Ptolemy I Soter (; , "Ptolemaĩos Sōtḗr" "Ptolemy the Savior"; c. 367 BC – January 282 BC) was a companion and historian of Alexander the Great who succeeded to his empire. Ptolemy became ruler of Egypt (323–282 BC) and founded the Ptolemaic dynasty which ruled it for the next three centuries, turning Egypt into a Hellenistic kingdom and Alexandria into a center of Greek culture. Ptolemy was the son of Arsinoe of Macedon by either her husband Lagus or Philip II of Macedon, the father of Alexander. Ptolemy was one of Alexander's most trusted companions and military