After the death of Spitamenes and his marriage to Roxana (Roshanak in Bactrian) to cement his relations with his new Central Asian satrapies, Alexander was finally free to turn his attention to the Indian subcontinent. Alexander invited all the chieftains of the former satrapy of Gandhara, in the north of what is now Jhelum River, Pakistani region (Mordern History) to come to him and submit to his authority. Omphis, ruler of Taxila, whose kingdom extended from the Indus to the Hydaspes, complied, but the chieftains of some hill clans, including the Aspasioi and Assakenoi sections of the Kambojas (known in Indian texts also as Ashvayanas and Ashvakayanas), refused to submit.
In the winter of 327/326 BC, Alexander personally led a campaign against these clans; the Aspasioi of Kunar valley, the Guraeans of the Guraeus valley, and the Assakenoi of the Swat and Buner valleys. A fierce contest ensued with the Aspasioi in which Alexander himself was wounded in the shoulder by a dart but eventually the Aspasioi lost the fight. Alexander then faced the Assakenoi, who fought bravely and offered stubborn resistance to Alexander in the strongholds of Massaga, Ora and Aornos. The fort of Massaga could only be reduced after several days of bloody fighting in which Alexander himself was wounded seriously in the ankle. According to Curtius, “Not only did Alexander slaughter the entire population of Massaga, but also did he reduce its buildings to rubbles”. A similar slaughter then followed at Ora, another stronghold of the Assakenoi. In the aftermath of Massaga and Ora, numerous Assakenians fled to the fortress of Aornos. Alexander followed close behind their heels and captured the strategic hill-fort after the fourth day of a bloody fight. This fight was the challenge Alexander was looking for, an army with huge elephants that were almost able to defeat Alexander.