Although it had unified China, the Western Jin never succeeded in establishing an autocratic imperial institution, that is, one capable of preserving ultimate power for the emperor and preventing dissension and power struggles. The imperial family's power was threatened by the families of empresses, especially the Jia family, who were suspected of arranging the assassination of the previous empress and her family as well as more than one heir to the throne. Nor was it possible for the emperors fully to control the civil service. The system of recruitment to government posts that had been instituted by the Wei - the 'nine rank system'- had degenerated from a system of local assessment of character to the standing of candidate's family. The Jin dynasty allowed further erosion of land to imperial princes. Gaining such resources spurred the princes' fratricidal instincts and culminated in a series of bloody struggles over succession. Each prince sought out allies, including generals and non-Chinese chieftains with troops, and full scale civil war raged in and near the capital between 291 and 305.