The philosophy of Stoicism was started in Hellenistic Athens, by Zeno of Citium, who had been trained in the philosophy of the Cynics, and spread to Rome where it was embraced by many Romans, including the Republican thorn in Julius Caesar's side, Cato the Younger.
The goal of Stoicism was to avoid suffering by leading a life of apatheia (whence, apathy), which means objectivity, rather than not caring, and self control. The Stoic's life should be based on reason and in harmony with the universe. Instead of avoiding the community and its potential temptations, like ascetics, Stoics felt themselves to be part of a universal community of man.
Stoicism and Epicureanism were the two main competing philosophies of the Romans.
Originally the Stoics were the followers of Zeno, but they came to be known for the location of their school, the painted porch/colonnade or stoa poikile.