Naczelnik () is the Polish word for Leader. It was first used as an official title by Tadeusz Kościuszko during the Polish revolutions of the 18th Century. In its Kościuszko form the title was used to signify commander of the uprising, or the modern day equivalent of head of state. Following World War I, changes in the Polish Military force structure eliminated the rank of Naczelnik and replaced it with the more modern and Western sounding rank of Field Marshal (Marszałek).