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 II Philadelphus in the Library of Alexandria Ptolemy II Philadelphus in the Library of Alexandria Ptolemy Philadelphus in the Library of Alexandria is an 1813 oil on canvas painting by Vincenzo Camuccini. It is now in the National Museum of Capodimonte in Naples. The work was commissioned by Napoleon I along with "Charlemagne Ordering Italian Scholars to Found the University of Paris", both for the central hall of Rome's Palazzo del Quirinale. It shows Ptolemy II Philadelphus in red robes among several philosophers in the Library of Alexandria. The artist had recently returned to Italy from Paris and decided to accept the commission. "Ptolemy" was then moved