Which ancient Greek philosopher did Alexander meet in Corinth?

The ancient Greek philosopher Alexander met in Corinth was Diogenes of Sinope.

Diogenes was one of the best-known philosophers of Cynicism, a movement that rejected luxury, social status and artificial conventions. He was famous for embracing an extremely simple way of life and for speaking bluntly to powerful people. According to the traditional story, he was living near Corinth when Alexander visited him.

Alexander reportedly asked whether Diogenes wanted anything. The philosopher replied that Alexander should move aside because he was blocking the sunlight. The encounter supposedly impressed Alexander, who later said that if he were not Alexander, he would choose to be Diogenes.

The anecdote survives in ancient writers including Plutarch and Diogenes Laërtius, but its exact historical details cannot be proved. It is often retold as a contrast between political power and philosophical independence. Diogenes was not Plato, Socrates or Epicurus: those were separate Greek philosophers from different periods and traditions.