Aristo came to be regarded as a marginal figure in the history of Stoicism, but in his day, he was an important philosopher whose lectures drew large crowds. Eratosthenes, who lived in Athens as a young man, claimed that Aristo and Arcesilaus were the two most important philosophers of his age. But it was the more moderate Zeno, not the radical Aristo, whose views would win out. Chrysippus, (head of the Stoic school from c. 232 to c. 206 BC), systemized Stoicism along the lines set down by Zeno, and in doing so, was forced to repeatedly attack Aristo: