The Cambridge History of India, Vol. I: Ancient India v1.c25.112

v1.c25.112

When the satrap of Parthia, a Persian, had brought down a body of Thracian reinforcements from Irān, Alexander moved across the Acesines (Chenāb), probably in the neighbourhood of Siālkot, having now nothing but physical difficulties to contend with³. The passage of the river brought him near the frontiers of the other Paurava. This chieftain's envoys had been for some time past carrying Alexander his homage; but his calculations had been completely upset when he saw the hated kinsman, whom he had pictured humbled before him by the power of the foreigners, retained at Alexander's side as an honoured friend. It made his own position a dangerous one and he fled before the approach of the Europeans⁴. The king pressed onwards to the next river, the Hydraōtes (Rāvi), leaving, of course, strong posts at various points behind him, to secure his communications. From the banks of the Hydraōtes he detached a body of troops under Hephaestion to occupy the territory of the fugitive Paurava, and annex all the land between the Acesines and the Hydraōtes to the realm of Porus his friend. Any free tribes within that region were to be taught to recognise their new prince's authority. Hephaestion was also to begin the walls of a city upon the Acesines—possibly⁵ an older native town commanding the road over the river, now to be rebuilt and fortified on Hellenic principles¹. Alexander himself passed on eastwards over the Hydraōtes.