Trebbia (Second Punic War).
Fought December B.C. 218, between 26,000 Carthaginians[Carthaginians], 6,000 being cavalry, under Hannibal, and 40,000 Romans under the Consul Sempronius. Sempronius' colleague, Scipio, had been wounded a few days before in a skirmish, and Sempronius, contrary to his advice, being in sole command, crossed the Trebbia to attack the Carthaginians. The Romans fought with determination, and the issue was for some time in doubt, but finally a charge of the Carthaginian horse, under Mago, against their left flank, threw the legionaries into confusion, and they were routed with enormous loss.