The Rasūlid Sultanate of Yemen (626-858/1229-1454) offers a new but rather singular evidence in the debate on state archives in the Medieval Arabic Lands. The existence of several books of administrative documents voluntarily preserved, constituting an extremely rich set of "Rasulid archives" is here put into perspective with the works written by the rulers themselves. All these archives and royal books aim apparently to replace Yemen, its territory, its products and its people in the horizon of universal knowledge. This paper deals particularly with two distinct types of administrative knowledge: how to describe the Yemeni land and how to identify the men who served the Sultanate? In these two fields, a distinct sultanic language is gradually forged, by borrowing heavily to dominant forms of the astronomical science and the biographical writing.