However, staging the attack on Goguryeo took much human and other tolls. The building of a fleet and the shipping of food and other supplies to the base of operations, Zhuo Commandery (涿郡, roughly modern Beijing) caused major disruptions in the farming cycle and massive deaths among those conscripted to ship the supplies to Zhuo Commandery. In response, in 611, in northern China, those who refused to be conscripted began to revolt as agrarian rebels, led by leaders such as Wang Bo (王薄) and Liu Badao (劉霸道). While Emperor Yang initially did not consider these rebels serious threats, the local governmental militias were unable to quell them.