Note 132 — Chapter XXV · —Alexander finding the army unwilling to advance beyond the Hyphasis, convokes his officers and addresses them on the subject
Reading edition
The Tanais is properly the Don, but Alexander meant by it the Jaxartes, which formed the eastern boundary of the Persian empire, and which he had crossed to attack the nomadic Skythians, who had made threatening demonstrations against him on the right or northern bank (v. the 16th and 17th chapters of the fourth book).