Euclid They follow the same logical structure as "Elements", with definitions and proved propositions. Other works are credibly attributed to Euclid, but have been lost. The European Space Agency's (ESA) Euclid spacecraft was named in his honor. Euclid Euclid (; – "Eukleídēs", ; fl. 300 BC), sometimes given the name Euclid of Alexandria to distinguish him from Euclides of Megara, was a Greek mathematician, often referred to as the "founder of geometry" or the "father of geometry". He was active in Alexandria during the reign of Ptolemy I (323–283 BC). His "Elements" is one of the most influential works in the
Ptolemaic cult of Alexander the Great propaganda to support the claims of his own dynasty. As part of this effort, Alexander was elevated from a simple patron god of Alexandria to the status of a state god for the Greek populations of the entire Ptolemaic empire, even beyond the confines of Egypt. During the early Ptolemaic dynasty (), Ptolemy I began the construction of the Tomb of Alexander the Great in Alexandria (the , "sēma", ), and appointed a priest (, "hiereus") to conduct religious rites there. This office quickly advanced to become the highest priesthood in the Ptolemaic Kingdom, its prominence underscored by its eponymous