the Battle of Ain Jalut forced him to return to the Middle East. Berke capitalized on the Mamluk victory by invading the Ilkhanate, beginning the Berke–Hulagu war. Ariq Böke allied with Berke Khan of the Golden Horde and Alghu of the Chagatai Khanate. Hulagu of the Ilkhanate was the sole ally of Kublai Khan. Berke supported Ariq Böke because he was resentful of Hulagu, who had close ties with Kublai. Hulagu and Berke, however, became occupied with their own war and could not intervene in the Toluid Civil War. Kublai had access to supplies from the fertile lands of China, while Ariq Böke had to import resources to Karakorum in the semi-arid steppes. Kublai Khan depended on these supplies from China and therefore needed Chinese popular support to win the civil war. Kublai ingratiated himself to his subjects with the help of his Chinese advisers. He presented himself as a sage emperor capable of uniting the Chinese, Korean and his fellow Mongols. While calling out Ariq Böke as a destructive usurper. Kublai promised to reduce taxes, modeled his government institutions to resemble those of the Chinese dynasties, and adopted the era name of Zhongtong, which means "moderate rule". His policies were popular in northern China, but had no impact on his relations with the Southern Song. The Song invaded while Kublai was preoccupied with the civil war, and recovered territory previously lost to the Mongols. Kublai dispatched a diplomat, Hao Jing, to discuss the prospects of a peaceful resolution to the war with the Southern Song. The Song, however, rejected Kublai's overtures and imprisoned Hao for the next decade. Kublai now controlled three of the four possible supply lines to Karakorum. Kadan, Kublai's Ögedeid ally, defended the territories of the former Western Xia from Ariq Böke and commanded the forces stationed in Gansu. Kublai's troops guarded the area surrounding Yan (modern Beijing). The only supply line still open to Ariq Böke was the Yenisei River valley in the northwest. When Kublai's army advanced towards Karakorum in late 1260, Ariq Böke retreated from Karakorum to a tributary of the Yenisei. The oncoming winter then compelled Kublai and Ariq Böke to encamp their armies and wait for spring. In the interim, Kublai acquired more supplies and men. He fortified Yan and the border defenses of northern China. Kadan defeated and executed Alandar, a general sent to secure the vital Central Asian trade