千葉氏
The imperial court gradually extended its authority over the three provinces in the Nara (710 – 794) and Heian (794 – 1185) periods. Shōen feudal estates were established across the three provinces, and the region became an important source of tax revenue, agricultural and other products to the capital in Kyoto. As the Heian period progressed, however, the kokushi provincial governors came to exert military power independent of the central government in Kyoto. The Chiba clan broke entirely with the imperial court and was instrumental in the establishment of the Kamakura shogunate.