Foundations of geometry different sets of axioms for Euclidean geometry, any of these can replace the Euclidean parallel postulate. The following partial list indicates some of these theorems that are of historical interest. Absolute geometry is a geometry based on an axiom system consisting of all the axioms giving Euclidean geometry except for the parallel postulate or any of its alternatives. The term was introduced by János Bolyai in 1832. It is sometimes referred to as neutral geometry, as it is neutral with respect to the parallel postulate. In Euclid's "Elements", the first 28 propositions and Proposition I.31 avoid using the parallel postulate,
Library of Alexandria largest and most significant libraries of the ancient world, but details about it are a mixture of history and legend. The earliest known surviving source of information on the founding of the Library of Alexandria is the pseudepigraphic "Letter of Aristeas", which was composed between 180 and 145 BC. The "Letter of Aristeas" claims that the Library was founded during the reign of Ptolemy I Soter ( 323– 283 BC) and that it was initially organized by Demetrius of Phalerum, a student of Aristotle who had been exiled from Athens and taken refuge in Alexandria within the Ptolemaic court. Nonetheless,