Short answers, pulled from the story.
Euclid lived around 300 BC in Alexandria under the rule of Ptolemy I. No contemporary records confirm his birth date or place of origin, though medieval Islamic sources claimed he was born in Tyre and died in Damascus.
The Elements stands as a thirteen-book treatise that dominated geometry until the early 19th century. Book one begins with twenty definitions for lines, angles, and regular polygons before presenting ten assumptions grouped into five postulates and five common notions.
At least five works attributed to Euclid have survived including Catoptrics, The Data, On Divisions, Optics, and Phaenomena. These texts follow the same logical structure as the Elements with definitions and proved propositions.
A papyrus fragment dated roughly 100 AD found at Oxyrhynchus contains diagrams accompanying Book II, Proposition 5. This physical evidence proves the work circulated by the first century.
Renaissance scholar Peter Ramus eventually proved this identification false through chronological contradictions after Byzantine scholars mixed him up with an earlier philosopher named Euclid of Megara. The earlier man was a pupil of Socrates who appeared in Plato's dialoges.