The ancient Greek historian Diodorus Siculus said the Romans marched and crossed the River Tiber. He is the only ancient historian who placed the battle on the right bank of the river. The Romans lined up their best troops, 24,000 men, in the plain and placed the weakest troops in the hill. The Celts also lined up and placed their best men on the hill and easily won the clash there. The bulk of the Roman soldiers in the plain fled to the river in a disorderly manner and impeded each other. The Celts killed the men in the rear. Some Romans tried to cross the river wearing their armour, which, according to Diodorus, they prized more than their lives, but that weighed them down. Some drowned and some managed to reach the bank further downstream with great effort. As the Gauls kept killing the Romans, the soldiers then threw their arms away and swam across the river. The Gauls threw javelins at them. Most of the survivors fled to the city of Veii. Some returned to Rome and reported that the army had been destroyed.