A largely missing picture until recently, was the fate of public lands (kokugaryo) during the Muromachi period, and the role of the "shugo" lords in their encroachment on them. Public lands (kokugaryo) during the Heian period were distinguished from private lands of the estates ("shōen"), because the latter were immune from state taxation. Before the rise of private estates, the only kind of lands were public lands maintained under the old civil administration. With the rise of private estates called "shōen", during the Heian period, public lands by no means disappeared: in details, the public lands differed very little from private estates. Both were owned by absentee proprietors. They differed only in terms of administration: private estates were directly managed by noble officials, whereas, public lands were managed by the civil governors (kokuga or kokushi) on behalf of the former.