Church bells rang, cannon shots were fired and the ships in the harbor sounded a welcome to celebrate the birth of twins for Monaco's royal couple. Princess Charlene gave birth on Wednesday to a boy and a girl, the royal couple's first children.
According to Monaco's Constitution, the boy, named Jacques, will be first-in-line to the throne, and not his twin sister, Gabriella.
"The Princess and the children are doing well," a royal announcement said.
The royal twins Gabriella Therese Marie and Jacques Honore Rainier - born to Charlene, 36, and Prince Albert II, 56 - are heirs to the centuries-old Grimaldi dynasty that rules the wealthy principality.
Prince Albert is the son of the late Prince Rainier III and actress Grace Kelly, who set aside a career in Hollywood to become Princess Grace. She died after a car crash in 1982.
Prince Albert II and Princess Charlene of Monaco have announced they are expecting their first child, who will be heir to the throne of the tiny principality.
The couple, who wed in 2011, released a short statement describing their "immense joy".
Albert, 55, has fathered two children prior to marrying the South African former Olympic swimmer Charlene, but neither has a claim on the throne because they were born out of wedlock.
The couple's baby will replace Albert's older sister, Princess Caroline, as heir to the throne.
Germany's bumper sporting weekend has continued with Nico Rosberg claiming victory in Formula 1's flagship Monaco Grand Prix ahead of his countryman Sebastian Vettel.
Vettel's Red Bull teammate Mark Webber was third, ahead of Rosberg's Mercedes teammate Lewis Hamilton.
McLaren's Jenson Button was the next best placed Brit in sixth, while Paul Di Resta was ninth in his Force India and Marussia's Max Chilton finished 14th.
Today's race came after German football giants Bayern Munich were crowned UEFA Champions League winners.
They beat Borussia Dortmund 2-1 in the competition's first final competed by two teams from the Bundesliga.