When Yesün Temür died in Shangdu in 1328, Tugh Temür was recalled to Khanbaliq by the Qipchaq commander El Temür. He was installed as the emperor (Emperor Wenzong) in Khanbaliq, while Yesün Temür's son Ragibagh succeeded to the throne in Shangdu with the support of Yesün Temür's favorite retainer Dawlat Shah. Gaining support from princes and officers in Northern China and some other parts of the dynasty, Khanbaliq-based Tugh Temür eventually won the civil war against Ragibagh known as the War of the Two Capitals. Afterwards, Tugh Temür abdicated in favour of his brother Kusala, who was backed by Chagatai Khan Eljigidey, and announced Khanbaliq's intent to welcome him. However, Kusala suddenly died only four days after a banquet with Tugh Temür. He was supposedly killed with poison by El Temür, and Tugh Temür then remounted the throne. Tugh Temür also managed to send delegates to the western Mongol khanates such as Golden Horde and Ilkhanate to be accepted as the suzerain of Mongol world. However, he was mainly a puppet of the powerful official El Temür during his latter three-year reign. El Temür purged pro-Kusala officials and brought power to warlords, whose despotic rule clearly marked the decline of the dynasty.