His conflict with Charles Robert forced him to fight on two fronts. He could continue the war against his brother after Serbian noblemen rose up against Milutin in the early 1310s. The Serbian prelates remained loyal to Milutin and helped him to hire Tatar, Jassic and Turkish mercenaries. After Milutin inflicted a decisive defeat on Dragutin in late 1311 or 1312, the prelates mediated a peace treaty between them most probably in 1312. Dragutin had to acknowledge his brother as the lawful king, but his Serbian appanage (including the silver mine at Rubnik) was fully restored to him. Dragutin sent reinforcements to help his brother's fight against the powerful Ban of Croatia, Mladen II Šubić of Bribir, in 1313. According to Krstić, Dragutin obviously made a peace treaty with Charles Robert in Sremska Mitrovica in February 1314. In 1314 or 1316, Dragutin signed his brother's charter of the grant to the Banjska Monastery as "the former king".