Taira Kiyomori, the son of Emperor Shirakawa, was born in 1118 into the Taira warrior clan. The majority of his childhood and adolescence was spent in the imperial court. Kiyomori then spent the years from 1137 to 1156 as a daimyo (provincial governor).
Then, in 1156, Kiyomori assumed control of the Taira family. For the next four years, Kiyomori's leadership would be tested in both the Hogen and Heiji wars. In 1160, in the Heiji war, Kiyomori aided Go-Shirakawa against a coup, and claimed a decisive victory over the Minamoto clan, their sworn rivals.
Having expelled the Minamoto family from Kyoto, Kiyomori claimed the position of prime minister in 1167, and was the first warrior clansman to hold such a position. By doing this, Kiyomori was able to manipulate the power structure of the court by marrying his daughters into the imperial family, and assigning Taira clansmen to official positions. Kiyomori then went so far as to move the court to his own domain after two failed revolts (one in 1177, and one in 1180). However, this caused many disputes and arguments, and Kiyomori was forced to return the court to Kyoto only six months later.
Before dying in 1181 Kiyomori replaced himself with his grandson, who would become Emperor Antoku. Taira Kiyomori is remembered as a ruthless, unforgiving tyrant. He is also credited for playing a key role in ending the classical Heian golden age.
http://www.compsoc.net/~gemini/simons/historyweb/taira-kiyomori.html
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