Prince Albert II formally ascended Monaco's throne in a day of ceremony that mixed royal pomp with remembrance of his late father, Rainier III.
The festivities started with a solemn Mass in Monaco's cathedral, attended by foreign dignitaries and European royalty.
It was an emotional ceremony - Prince Albert's sisters Princess Caroline, pictured, and Princess Stephanie, cried during the Mass.
Among the royal guests were the UK's Prince Edward and his wife Sophie, the Countess of Wessex
Sweden's Crown Princess Victoria wore an eye-catching outfit.
Emmanuel Philibert of Savoy, grandson of Italy's last king, and his wife Clotilde Courau, also attended.
Albert automatically assumed royal powers on his father's death in April, and was sworn in as head of state in July.
After the Mass, Prince Albert and his two sisters watched a military parade.
The 47-year-old then enjoyed an afternoon at the football, watching Monaco play Saint-Etienne.
He and his family attended the opera in the evening to watch a performance of Rossini's The Voyage to Reims.