Trade was also restricted and travel could be undertaken only with documents issued by the ambans. The ambans were to review all judicial decisions. However, according to Warren Smith, these directives were either never fully implemented, or quickly discarded, as the Qing were more interested in a symbolic gesture of authority than actual sovereignty.[78] In 1841, the Hindu Dogra dynasty attempted to establish their authority on Ü-Tsang but were defeated in the Sino-Sikh War (1841–1842).