A Constitutional Monarchy is a system of government seen in many if not all governments in Renaissance Kingdoms realms today.
Constitutional Monarchy involves a monarch who shares powers with a parliament or congress of representative individuals. It is seen foremost today with figures such as regents and elected kings or queens.
This is the most persistent type of government seen at this time in Renaissance Kingdoms, with most sovereigns serving long terms as King or Queen and there have also been elected Regents even in times of Absolute Monarchy or the transition period.
The Constitutional Monarchy can be seen in the Kingdom of England with it's Parliament consisting of all County Council members throughout the Kingdom, and then the elected Sovereign who coerces with the Dukes and Duchesses, and under them the Mayors, to govern over-all national policy. There are some arguments and causes for change however, as some say the current County Council member qualifications for Parliament can create sectionalist factions.