The rota (or rotation) system or the lestvitsa system (from the Old Church Slavonic word for "ladder" or "staircase") is a historiographical concept introduced by historian Sergei Soloviev in 1860, attempting to describe a system of collateral succession practiced (though imperfectly) in Kievan Rus', later appanages, and early the Principality of Moscow.[1] In this system, the throne passed not linearly from father to son (agnatic primogeniture), but laterally from brother to brother (usually to the fourth brother) and then to the eldest son of the eldest brother who had held the throne.[1]