Prince Rainier III of Monaco revises the principality's constitution, devolving some of his power to advisory and legislative councils.

Rainier III was Prince of Monaco from 1949 to his death in 2005. Rainier ruled the Principality of Monaco for almost 56 years.

Monaco, officially the Principality of Monaco, is a sovereign city-state and microstate on the French Riviera a few kilometres west of the Italian region of Liguria, in Western Europe, on the Mediterranean Sea. It is a semi-enclave bordered by France to the north, east and west. The principality is home to nearly 39,000 residents as of the 2020s, of whom about 9,883 are Monégasque nationals. It is recognised as one of the wealthiest and most expensive places in the world. The official language of Monaco is French. Monégasque, English and Italian are also spoken and understood by many residents.

A principality is a type of monarchical state or feudal territory ruled by a prince or princess. It can be either a sovereign state or a constituent part of a larger political entity. The term "principality" is often used to describe small monarchies, particularly those in Europe, where the ruler holds the title of prince or an equivalent.

The Constitution of Monaco, first adopted in 1911 after the Monégasque Revolution and heavily revised by Prince Rainier III on 17 December 1962, outlines three branches of government, including several administrative offices and a number of councils, who share advisory and legislative power with the prince.