The Order of Knights of the Hospital of Saint John of Jerusalem (Latin: Ordo Fratrum Hospitalis Sancti Ioannis Hierosolymitani), also known as the Order of Saint John, Order of Hospitallers, Knights Hospitaller, or Hospitallers, was the name of the medieval Catholic military order that preceded the contemporary Sovereign Military Order of Malta, which remains a sovereign subject of international law. It was headquartered variously in the Kingdom of Jerusalem, Rhodes and Malta, until it became known by its current name.