Euclid 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 history of mathematics, serving as the main textbook for teaching mathematics (especially geometry) from the time of its publication until the late 19th or early 20th century. In the "Elements", Euclid deduced the theorems of what
Ptolemy X Alexander I throne, and replacing the former sarcophagus with one made of glass. The citizens of Alexandria were so outraged at this act that they exiled him again almost immediately and attempted to wipe out all record of him. He would later be killed on his way to Cyprus. When Ptolemy X died, Ptolemy IX regained the throne. When Ptolemy IX died in 81 BC, Ptolemy X's wife Berenice III took over the throne for six months. Ptolemy X Alexander I Ptolemy X Alexander I (, "Ptolemaĩos Aléxandros") was King of Egypt from 110 BC to 109 BC and 107 BC till