all accounts mentally disabled, possibly as a result of poisoning by Olympias. News of Philip's death roused many states into revolt, including Thebes, Athens, Thessaly, and the Thracian tribes north of Macedon. When news of the revolts reached Alexander, he responded quickly. Though advised to use diplomacy, Alexander mustered 3,000 Macedonian cavalry and rode south towards Thessaly. He found the Thessalian army occupying the pass between Mount Olympus and Mount Ossa, and ordered his men to ride over Mount Ossa. When the Thessalians awoke the next day, they found Alexander in their rear and promptly surrendered, adding their cavalry to Alexander's force. He then continued south towards the Peloponnese. Alexander stopped at Thermopylae, where he was recognized as the leader of the Amphictyonic League before heading south to Corinth. Athens sued for peace and Alexander pardoned the rebels. The famous encounter between Alexander and Diogenes the Cynic occurred during Alexander's stay in Corinth. When Alexander asked Diogenes what he could do for him, the philosopher disdainfully asked Alexander to stand a little to the side, as he was blocking the sunlight. This reply apparently delighted Alexander, who is reported to have said "But verily, if I were not Alexander, I would like to be Diogenes." At Corinth, Alexander took the title of Hegemon ("leader") and, like Philip, was appointed commander for the coming war against Persia. He also received news of a Thracian uprising. Balkan campaign Before crossing to Asia, Alexander wanted to safeguard his northern borders. In the spring of 335 BC, he advanced to suppress several revolts. Starting from Amphipolis, he travelled east into the country of the "Independent Thracians"; and at Mount Haemus, the Macedonian army attacked and defeated the Thracian forces manning the heights. The Macedonians marched into the country of the Triballi, and defeated their army near the Lyginus river (a tributary of the Danube). Alexander then marched for three days to the Danube, encountering the Getae tribe on the opposite shore. Crossing the river at night, he surprised them and forced their army to retreat after the first cavalry skirmish. News then reached Alexander that the Illyrian chieftain Cleitus and King Glaukias of the Taulantii were in open revolt against his authority. Marching west into Illyria, Alexander defeated each in turn, forcing the two rulers to flee with their troops. With these victories, he secured his northern frontier. Destruction of Thebes While Alexander campaigned