The House of Khalifa is the ruling family of the Kingdom of Bahrain. They profess Sunni Islam and belong to the Anizah tribe. Some members of this tribe joined the Utub alliance which migrated from Najd in central Arabia to Kuwait, then ruled all of Qatar, more specifically Al Zubarah, which they built and ruled over before settling in Bahrain in the early 17th century. The current head of the family is King Hamad bin Isa Al Khalifa, who became the Emir of Bahrain in 1999 and proclaimed himself King of Bahrain in 2002, in fact becoming a constitutional monarch.