Alexander was an explorer as well as a conqueror, and his disappointment at this enforced withdrawal from the prosecution of his march must have been that of a man who was within reach of the goal and just failed to attain it. According to the geographical notions of his day, he was near the certain limit of the world; he knew nothing of the great Indian peninsula, and of course nothing of the vast extent of Siberia or the Chinese Empire. He supposed that the Ganges flowed into an eastern sea which was continuous with the Caspian and which washed the shores of Scythia and the base of the high mountains he had lately passed through. On the river Hydaspes, a fleet had already been under construction; as soon as it was ready he embarked on it a part of his best troops, while the mass of the army, in two divisions, moved down the stream. The route followed was along the Hydaspes to its confluence with the Akesines, then down this stream to the Indus and the Indus itself to the Delta. From the military point of view, this concluding stage of the Indian expedition offers little of special interest. The inhabitants of the country either submitted to or fled from the Greek army, and various strongholds were taken by storm. In an assault on one of them, held by the Malians, who dwelt in the southern Punjab, the king, who had pressed forward in the midst of the enemy, found himself separated from the main body of his followers and was dangerously wounded. In the region the army traversed several colonies were founded; another Alexandria rose at the point where the Akesines flows into the Indus, and at Pattala a harbor and navy yard were built. The conquered portion of India was organized in three satrapies, one of which was under Porus, who had a free position as a vassal prince, for in his territory there were no Macedonian garrisons. But the real subjugation of the country had not been effected by the spectacular march through it; as soon as the Greeks turned their backs, an uprising took place. Before the whole army reached Pattala, a part had been detached with directions to march west to Arachosia, and to wait in Caramania till it was joined there by the main division. The fleet was placed under the command of Nearchus, a Cretan, who was to take it along the coast of the Indian Ocean and finally into the Persian Gulf. Alexander, at the head of the rest of the army, took the road through Gedrosia.