Euclid of Megara, a Greek philosopher, a disciple of Socrates, was influenced by the Eleatics (q.v.); founded the Megaric school of Philosophy, whose chief tenet is that the “good,” or that which is one with itself, alone is the only real existence.
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Euclid of Alexandria * Eudæmonism