Kublai continued the assault against the Song, gaining a temporary foothold on the southern banks of the Yangtze. By the winter of 1259, Uriyangkhadai's army fought its way north to meet Kublai Khan's army, which was besieging Ezhou in Hubei. Kublai made preparations to take Ezhou, but a pending civil war with his brother Ariq Böke—a rival claimant to the Mongol Khaganate—forced Kublai to move back north with the bulk of his forces. In Kublai's absence, the Song forces were ordered by Chancellor Jia Sidao to make an immediate assault and succeeded in pushing the Mongol forces back to the northern banks of the Yangtze. There were minor border skirmishes until 1265, when Kublai won a significant battle in Sichuan.