On 27 July 1214, the opposing armies suddenly discovered that they were in close proximity to one another, on the banks of a little tributary of the River Lys, near the bridge at Bouvines. It being a Sunday, Philip did not expect the allied army to attack, as it was considered unholy to fight on the Sabbath. Philip's army numbered some 7,000, while the allied forces possessed around 9,000 troops. The armies clashed at what became known as the Battle of Bouvines. Philip was unhorsed by the Flemish pikemen in the heat of battle, and were it not for his mail armor he would have probably been killed. When Otto was carried off the field by his wounded and terrified horse, and the Count of Flanders was severely wounded and taken prisoner, the Flemish and Imperial troops saw that the battle was lost, turned, and fled the field. The French did not pursue.