A Visigothic presence in Thrace would provide the Romans with a defensive deterrent in that unpopulated region. What Valens did not realize, however, was how many Visigoths actually wanted to enter into the empire. When an estimated 200,000 Visigoths crossed over the Danube River, Valens found that he could not feed them, and the Visigoths were forced to challenge the Roman army, defeating it at the battle of Adrianople in 378.