In parliamentary constitutional monarchies, the legitimacy of the unelected head of state typically derives from the tacit approval of the people via the elected representatives. Accordingly, at the time of the Glorious Revolution, the English parliament acted of its own authority to name a new king and queen (the joint monarchs Mary II and William III); likewise, Edward VIII's abdication required the approval of each of the six independent realms of which he was monarch. In monarchies with a written constitution, the position of monarch is a creature of the constitution and could quite properly be abolished through a democratic procedure of constitutional amendment, although there are often significant procedural hurdles imposed on such a procedure (as in the Constitution of Spain).