The article recreates personal crew of royal castles in the Kingdom of Poland at the turn of the Middle Ages and the Early Modern period. The oldest known listings of the personnel of 31 royal castles from the territory of the Polish state were utilized, found in inventories and ledgers of capitanates (starostwo), mostly from the late 15th and first half of the 16th centuries, which are rarely used by researchers. Treating the castle as the centre of royal estates and taking into account all its administrative and economic functions, practically the whole mechanism of managing the capitanate (or a set of royal estates) was presented. Within the permanent crew there were three categories of people: officials of the capitanate, servants, and military and police functionaries (including the military crew). The whole of the crew usually did not exceed 20 people, only exceptionally reaching 50 people (in several castles in the border areas). The military crew was quite small (typically 6-12 people). The majority of those living in castles were therefore civilians dealing with administrative and economic matters. Because of such small permanent crew, it was necessary to strengthen it in situations threatening the area from the outside (with peasants from royal estates and those of monasteries).