After Yoshitomo lost the war, Hirotsune followed the Heike clan; however, the internal conflict between Hirotsune, an heir to Tsunezumi, and his older brothers, Tsunekage and Tsuneshige, regarding the reigns of the Kazusa clan developed after his father, Tsunezumi, died.
義朝が敗れた後は平家に従ったが、父常澄が亡くなると、嫡男である広常と庶兄の常景や常茂の間で上総氏の家督を巡る内紛が起こった。