Euclid lived and taught in Alexandria at the same time as Ptolemy I was still wandering the halls of the Greta Library.
His main work the Elements of Geometry, and he was called Euclid of Alexandria, because that city is the only one with which he can be almost certainly connected.
The thirteen books of the Elements show mathematics at its most elegant, with problems solved in concise logical ways. Euclid’s Elements is so well organized that it remained the standard geometry textbook until the twentieth century.
He was probably educated in Athens and if so, he received his mathematical tarring at the Academy, which was the outstanding mathematical school of the fourth century and the only one where he could have gathered easily all the knowledge that he possessed.
Euclid the Alexandria died around 270 BC.
Euclid of Alexandria