Fujiwara no Michinaga (966-1028) was the most powerful of the Fujiwara sesshō. In 1016 he became regent (sesshō) for his nephew, emperor Go-Ichijō. In 1017 he was appointed chancellor, the most powerful position in the council of state. In 1019 he took the tonsure and retired from formal political life, but continued to wield enormous power through his son, whom he installed as kanpaku. To secure military power he allied himself with the Seiwa Genji, a clan of powerful provincial warriors. After Michinaga's death no Fujiwara leader was proved as able. The resurgance of the imperial house in the 1100s precipitated the military conflicts of the 1150s.