While Alexander campaigned north, the Thebans and Athenians rebelled once again. Alexander immediately headed south. While the other cities again hesitated, Thebes decided to fight. The Battle of Thebes was a battle that took place between Alexander III of Macedon and the Greek city state of Thebes in 335 BCE immediately outside of and in the city proper. After having been made Hegemon of the League of Corinth, Alexander had marched to the north to deal with revolts in Illyria and Thrace. The garrison in Macedonia was weakened and Thebes declared its independence. The Thebans refused to submit on merciful terms, and he assaulted the city, took it, and sold all the survivors into slavery. With the destruction of Thebes, mainland Greece again acquiesced in Alexander's rule. Alexander was now finally free to undertake the Persian campaign which had been planned for so long by his father.