"The earliest account based on Megasthenes occurs in Diodorus (1st century B.C.). Referring to the Ganges, he (II.37)3 writes: "Now this river which at its source is 30 stadia broad, flows from north to south, and empties its waters into the ocean forming the eastern boundary of the Gangaridai, a nation which possesses the greatest number of elephants and the largest in size. Owing to this, their country has never been conquered by any foreign king; for all other nations dread the overwhelming number and strength of these animals. Thus Alexander the Macedonian, after conquering all Asia, did not make war upon the Gangaridai, as he did on all others; for when he had arrived with all his troops at the river Ganges, and had subdued all the other Indians, he abandoned as hopeless an invasion of the Gangaridai when he learned that they possessed four thousand elephants well trained and equipped for war.""