The 13 states are based on historical Malay Kingdoms, and 9 of the 13 states, known as the Malay States, retain their royal families. The Federal King (titled "Yang di-Pertuan Agong") is elected (de facto rotated) among the nine rulers to serve a 5-year term. The nine "Malay States" have a hereditary Ruler as titular Head of state and an executive Chief Minister or "Menteri Besar" as politically responsible Head of government. The rulers of Johor, Kedah, Kelantan, Pahang, Perak, Selangor and Terengganu are styled Sultans (typically Islamic). Only Negeri Sembilan's elective ruler holds the rare, autochthonous Malay title of "Yang di-Pertuan Besar", whereas only the Ruler of Perlis is titled "Raja". Former British settlements and crown colonies of Penang and Malacca (both peninsular) and Sabah and Sarawak (both on Borneo) each have a federally appointed titular Governor (styled "Yang di-Pertua Negeri") and an executive Chief Minister or "Ketua Menteri".