Oyo, Oyo State, is the seat of the line of the rulers of Oyo. Their territory, a constituent rump state, is located in what is now Nigeria. Since the 1900 political absorption into Southern Nigeria of the kingdom that it once served as a metropolitan center, the traditional monarchy has been either a tool of British indirect rule or a legally recognised traditional polity within the republic of Nigeria. In the Yoruba language, the word 'oba' means ruler or king. It is also common for the rulers of the various Yoruba domains to have their own special titles. In Ọ̀yọ empire, the oba is referred to as the Aláàfin, meaning owner of the palace. List of Alaafins of Oyo