During the 1870s, power struggles between the rival valleys of Paro and Tongsa led to civil war in Bhutan, eventually leading to the ascendancy of Ugyen Wangchuck, the ''penlop'' (governor) of Trongsa. From his power base in central Bhutan, Ugyen Wangchuck defeated his political enemies and united the country following several civil wars and rebellions during 1882–85.