 However, he arrived too late to participate in the Battle of Mingolsheim on 27 April, where the Palatinate commander Count Ernst von Mansfeld crushingly defeated Lieutenant General Tilly of the Catholic League.On 27 April, George Frederick declared war on the Habsburgs and combined his forces with those of Mansfeld, so as to fight the Catholic League together.When they were inexplicably separated a few days later, George Frederick came under attack from Tilly, who was assisted by Spanish troops under Córdoba.