The expedition having been disposed of in various divisions, had orders to observe a due distance from each other in their movements, so that no confusion might arise, its speed being at the same time regulated so as to accommodate itself to the motions of the army on the shore. Three vast armies, moving in separate divisions, encumbered with baggage as well as with munitions of war, with no roads prepared for them, and, for the most part, following the sinuosities of the river, must have had numerous difficulties to surmount. It is, therefore, unlikely that they were able to maintain their combined movement with anything like order, or to average in their progress as much as the fifteen miles a day Dr. Vincent considers a fair estimate for them. Still less is it possible that they could have accomplished the six hundred stadia, or seventy miles, in the time Pliny has recorded. The estimate of Curtius of forty stadia, or four miles and three quarters a day, is unquestionably nearer the truth, as we know that the fleet was nine months floating down a distance of little more than one thousand miles. Moreover, there were constant delays and interruptions, arising from the arrangements Alexander considered it necessary to make with the different tribes and provinces through whose territory he had to advance. [Sidenote: Establishment of new cities on the banks of the Indus.] At the junction of the Acesines with the Indus, Alexander established his first city on the banks of that river. The site was judiciously chosen, as a city placed in such a position would necessarily partake of all the commerce that passed up the Indus, to be distributed by means of its various tributaries, from Candahar and Kâbul on the west, to Upper India and Thibet on the north and north-east: moreover, being the centre where all the streams united, it must, consequently, derive equal emoluments from the commerce that passed downwards to the coast.[265] From the establishment of this and of other cities on the banks of the Indus, all of which he fortified, it is evident that the Macedonian conqueror destined that river to be the eastern frontier of his empire, and saw that, by holding the command of it, he would combine, by means of a river navigation to the eastern portion of his dominions, a maritime commerce with the richest portions of the interior of India.