The Written Constitution of 1875 is the founding document of modern Tonga.  It created Government which is the Executive Body; Parliament which makes the laws and the Judiciary which upholds the laws. 

The King is the Chair of the Privy Council which is the highest body of Government and consents to all laws passed in Tonga.  It is made up of the Prime Minister and members of Cabinet. 

The Constitution of 1875 promoted chiefs and their estates into hereditary titled owners.  The role of Nobles is to protect and retain identity and uphold traditional heritage.  Parliament is made up of Nobles and Peoples representatives. 

The King opens and closes Parliament every year, as one of his duties as Sovereign leader of the nation.