Euclid 325-265 BC QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. • Author of The Elements – 13 books in all. – Standard textbook for Geometry for about 2000 years. • Taught in Alexandria, Egypt. Euclid’s Elements: The first 4 axioms A modern form of the axioms. 1. For every point P and every point Q not equal to P there exists a unique line that passes through P and Q. 2. For every segment AB and for every segment CD there exists a unique point E such that B is between A and E and the segment CD is congruent to segment BE. 3. For every point O and every point A not equal to O there exists a circle with center O and radius OA. 4. All right angles are congruent to each other. Euclid’s Elements: The Parallel Postulate 5. That, if a straight line falling on two straight lines make the interior angle on the same side less than two right angles, the two straight lines, if produced indefinitely, meet on that side on which are the angles less than two right angles.