Since the time when the position of gunji (de facto feudal rights) was captured by zuryo (the head of the provincial governors) and Shimosa no kami FUJIWARA no Chikamichi in 1136, Tsunetane and his family were likely to have struggled to develop the southern part.
保延2年（1136年）に受領・下総守藤原親通に郡司職（事実上の領主権）を奪われて以降、常胤一族は必死になってその南部を開発していたのかもしれない。