Diogenes dies at Corinth, nearly ninety by one account. One ancient writer says it was the same day Alexander died; modern scholars think that is likely legend.
Demetrius in his work On Men of the Same Name asserts that on the same day on which Alexander died in Babylon Diogenes died in Corinth.
In antiquity a philosopher's death was often read as a final statement on his teachings. The many accounts of Diogenes's death helped make him a lasting symbol of defiance of established authority.
Based on Wikipedia: Diogenes
In ancient Greece and Rome, a philosopher's death was often seen as a final statement on their teachings.
His memorable encounters, including that with Alexander the Great, along with various accounts of his death, have made him a lasting symbol of philosophical defiance to established authorities and artificial values.