Louis II, Prince of Monaco
On 26 June 1922, Prince Albert I died in Paris. Louis Grimaldi ascended to the throne as Louis II, Prince of Monaco. While his reign never achieved the grandeur of his father, Louis II left an indelible imprint on the tiny principality. In 1924 the Monaco Football Club was formed and in 1929, the first Grand Prix of Monaco automobile race was held, won by Charles Grover (aka "Williams") driving a Bugatti painted in what would become the famous British racing green color. He collected artefacts belonging to Napoleon I which are now assembled and displayed in the Napoleon Museum attached to the Royal Palace in Monte Carlo.
Rainier III, Prince of Monaco
As Prince of Monaco, Rainier was also responsible for the principality's new constitution in 1962 which significantly reduced the power of the sovereign. (He suspended the previous constitution in 1959, saying that it "has hindered the administrative and political life of the country.") The changes ended autocratic rule, placing power with the prince and a National Council of eighteen elected members.