The Greeks and Romans knew ivory first, and then became acquainted with the elephant. The island of Elephantina in the Nile was from the earliest times a seat of trade in the ivory tusks of the African elephant, and so acquired its name. Herodotus is the first to mention the elephant itself; Homer only refers to the ivory by the word "elephas." Aristotle in this, as in other matters, is more correct than later writers. He probably received first-hand information about the elephant from Alexander and some of his men after their Indian expedition. The Romans had an unpleasant first personal experience of elephants when Pyrrhus, King of Epirus, landed a number with his army and put the Roman soldiers to flight. But the Romans then, and continually in after-times, showed their cool heads and sound judgment in a certain contempt for elephants as engines of war. They soon learned to dig pits on the battlefield to entrap the great beasts, and they deliberately made for the elephants' trunks, hewing them through with their swords, so that the agonised and maddened creatures turned round and trampled down the troops of their own side. The Romans only used them subsequently to terrify barbaric people, and as features in military processions. But Eastern nations used them extensively in war. In A.D. 217 Antiochus the Great brought 217 elephants in his army against 73 employed by Ptolemy, at what was called "the Battle of the Elephants." The battle commenced by the charging head to head of the opposing elephants and the discharge of arrows, spears and stones by the men in the towers on their backs.