In the spring of 1249, a Guelph Romagnol army of the Lombard League advanced to the Panaro. The army was composed of 3,000 knights and 2,000-foot soldiers from the Margrave Azzo VII d'Este and 1,000 knights and 800-foot soldiers of Bolognese militias from Porta Stieri, Porta San Procolo, and Porta Ravegnana. The army was led by the Brescian Filippo Ugoni, who had victoriously defended Milan while besieged by Emperor Frederick II, and accompanied by Ottaviano degli Ubaldini, the Cardinal of Bologna.