The word "monarch" is derived from the Greek word monos archein, meaning "one ruler", and is referred to an absolute ruler in ancient Greece. Historically, monarchs have been absolute rulers. Such countries as Bhutan, Saudi Arabia and Oman are the few absolute monarchies remaining in the modern world but the constitutional monarchy has become a more common type of monarchy in which a king or queen rules with limits to their powers along with a governing body - the Parliament. Japan, Thailand, Norway and Sweden are among some of the countries governed by a constitutional monarchical system.