Alexander had begun planning the expedition two years before, in 329 BC, but had been delayed in carrying out the expedition by a series of revolts that had taken place in Aria, Sogdiana and Bactria. He was held up in putting down these revolts as he had been marching through the Hindu Kush mid-winter and decided to camp in the mountains. It was during this time that he founded the city of Alexandria ad Caucasum. This city was some twenty five miles north-west of modern Kabul, in Afghanistan.