Geographical description and historical narrative in the tradition on Alexander's expedition

Through geography it is possible better to understand the accounts of what actually happened, and probably also the different aim behind the stories related by those who joined Alexander’s great endeavour.Unfortunately only a few fragments from this rich production have sur- vived, through a selection that, on the one hand, limits our knowledge, but on the other allows us better to grasp the peculiarities of different works, as these fragments show us what was considered, in antiquity, the most significant and peculiar passages of the work they belonged to.I will consider here some fragments of Nearchus of Crete (FGrHist 133), Onesicritus of Astypalaea (FGrHist 134), Ptolemy son of Lagus (FGrHist 138) and Aristobulus of Cassandreia (FGrHist 139), related to Indian hydrography, and significant for several reasons. First of all because the attention to hydrography is a common element of the examined works due to the obviousimportance of rivers, which served as main roads and water routes for trade, and as natural borders and privileged places for sacrifices