The Order of Knights of the Hospital of Saint John of Jerusalem (Latin: Ordo Fratrum Hospitalis Sancti Ioannis Hierosolymitani), commonly known as the Knights Hospitaller (/ˈhɒspɪtələr/), was a medieval and early modern Catholic military order. It was headquartered in the Kingdom of Jerusalem until 1291, on the island of Rhodes from 1310 until 1522, in Malta from 1530 until 1798 and at Saint Petersburg from 1799 until 1801. Today several organizations continue the Hospitaller tradition, specifically the mutually recognized orders of St. John, which are the Sovereign Military Order of Malta, the Most Venerable Order of the Hospital of Saint John, the Bailiwick of Brandenburg of the Chivalric Order of Saint John, the Order of Saint John in the Netherlands, and the Order of Saint John in Swed