Although the Han Dynasty of China was firmly cemented into power and extended its imperial influence into Central Asia during the first half of the century, by the second half there was widespread corruption and open rebellion. This set in motion its ultimate decline, and in September 189, the Han general Dong Zhuo, after being summoned to the capital by He Jin to help quell the corrupt and powerful eunuch faction by serving as an intimidator to both them and the Empress Dowager, marched his army into Luoyang in light of He Jin's assassination and the subsequent slaughter of the eunuchs, taking over the capital and effectively becoming the de facto head of the government, although warlords and government officials quickly took against him in a campaign that, while failing to put him down, compelled Dong Zhuo to shift the seat of imperial power further west to Chang'an. As Dong Zhuo was killed in 192, the chaos in the wake of the collapse of centralized authority only continued, with various warlords attempting to vye for supremacy in order to establish or hold onto their authority within the decaying empire. Meanwhile, Dong Zhuo's former followers Li Jue and Guo Si were left to squabble amongst themselves, while the emperor himself eventually fled and returned to the ravaged city of Luoyang, but shortly thereafter, in 196, was given refuge by the warlord Cao Cao, who relocated him to the new capital city of Xu, from where Cao Cao could control the emperor. Cao Cao would only further exert his authority by defeating the powerful warlord Yuan Shao at the decisive Battle of Guandu in 200.