Originally, Kofuku-ji Temple had virtual governorship over Yamato Province, and its monk general Junsho TSUTSUI had become a virtual warring lord and ruled Yamato; however, when Junsho died, taking the advantage of the infancy of his heir Junkei TSUTSUI, Hisahide invaded Yamato in 1559 at the instruction of Nagayoshi, and deprived the Tsutsui clan of its estate and the Kofuku-ji Temple of its governorship.
同国は元々興福寺に守護の権限があり、興福寺の衆徒であった筒井順昭が戦国大名化して大和を平定していたが、順昭が急死すると後継者である筒井順慶が幼い事を幸いに、永禄2年（1559年）久秀は長慶の命令を受けて大和に侵攻し、筒井氏の所領と興福寺が持つ守護の地位を奪い取ったのである。