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
Pope Dioscorus I of Alexandria Coptic Orthodox and Greek Orthodox Patriarchates of Alexandria agreed to mutually recognize baptisms performed in each other's churches. Pope Dioscorus I of Alexandria Pope Dioscorus I of Alexandria, 25th Pope of Alexandria & Patriarch of the See of St. Mark. He was deposed by the Council of Chalcedon in 451 but was recognized as Patriarch by the Coptic Church until his death. He died on the Island of Gangra, Paphlagonia, in September 454. He is venerated as a saint by the Coptic and other Oriental Orthodox churches. Dioscorus served as the dean of the Catechetical School of Alexandria, and was