Fanzhen () was a governmental system involving administration through regional governors (jiedushi). The term fanzhen literally means "buffer town", and refers to the system of settling troops in strategic locations along the empire's border areas, which during the Tang Dynasty came under the control of provincial military governors, or jiedushi. As control of these fanzhen devolved from central authority into the hands of the local leaders, they at times became powerful enough to threaten the imperial Chinese central government during the Tang Dynasty, (618–907 CE) particularly during and after the An Shi Rebellion. This important example of the fanzhen system in action involved the case of An Lushan, the provincial governor and military commander who started this rebellion against Empero