荘園公領制が成立する12世紀には耕作者が公領・荘園のいずれを耕していようとも公領居住者は公民、荘園居住者は荘民であるとする原則、そして国司は公民には令制国の賦役はかけられるが荘民にはそれができないという原則が確立されていた（大治(日本)4年12月3日(旧暦)明法家勘文）。

By the twelfth century when the shoen koryo sei (The System of Public Lands and Private Estates) came into force, the rule, in which the residents of koryo were regarded as komin and the residents of shoen were regarded as shomin, regardless of whether the cultivator works in the fields that belong to koryo or shoen, was established; and further, the rule in which the Kokushi (an officer of local government) can impose the fueki (corvee) of the province on komin, but not on shomin, was founded on January 21, 1130, according to Myobo-ke kanmon (Report by Judicial Officials). - Wikipedia日英京都関連文書対訳コーパス