to present Duman to him. Some officials requested that Duman be executed, but Su made a plea on Duman's behalf—that he had promised Duman life before Duman surrendered—and Emperor Gaozong stated that while under the law, Duman should die, he would honor Su's promise, and so he spared Duman. On the other end of the Tang atmosphere of influence, on the Korean Peninsula, Baekje had been attacking the Tang ally Silla. Once Su returned from the Esegel campaign, Emperor Gaozong commissioned him to head over the sea to attack Baekje, in conjunction with Silla. Su quickly captured the Baekje capital Sabi, forcing Baekje's King Uija and his crown prince Buyeo Yung to surrender. Emperor Gaozong ordered that Baekje be annexed as Tang territory. Emperor Gaozong then followed up by commissioning Su, along with Qibi Heli, Liu Boying (), and Cheng Mingzhen (), to attack Goguryeo. In 660, Emperor Gaozong and Empress Wu toured Bian Prefecture (modern-day Taiyuan), and Empress Wu had the opportunity to invite her old neighbors and relatives to a feast. Later that year, Emperor Gaozong began to suffer from an illness that carried the symptoms of painful headaches, persistent dizziness, occasional seizures and loss of vision, generally thought to be hypertension-related or stroke, and Emperor Gaozong began to have Empress Wu make rulings on petitions and suggestions made by officials. It was said that Empress Wu had quick reactions and understood both literature and history, and therefore, she was making correct and error-free rulings. Emperor Gaozong's illness worsened over time, and lasted until his death. If he was well, he also would accept Empress Wu's help, asking her to read the documents to him, he consulted with her on important matters and write down the rulings he had issued. Even until midnight, when he was exploring the memorials, he had Empress Wu by his side to decide if anything went wrong, and he became very dependent on her advice over time, and, as usual, because of his illness, he allowed Empress Wu to act in his name. Thereafter, her authority rivaled Emperor Gaozong's, after this point on, Empress Wu became the undisputed power behind the throne until the death of Emperor Gaozong. Middle reign: Empress Wu's aggrandization of power Longshuo and Linde eras (661–666) Meanwhile, just after Su Dingfang left Baekje territory to attack Goguryeo, the Buddhist monk Dochim () and the former Baekje general Gwisil Boksin