“Her Royal Highness The Duchess of Cambridge was safely delivered of a son at 1101hrs,” the statement said. “The baby weighs 8lbs 7oz. The Duke of Cambridge was present for the birth.”

The boy, whose name has not yet been announced, joins siblings George, 4, and Charlotte, 2.

The male sex of the Duchess’s third baby with husband William, the Duke of Cambridge, is especially notable, since he will be the younger sibling of Princess Charlotte. Years ago, a new baby brother would have usurped Charlotte’s place in the line of succession to the throne, but that’s no longer the case. Royal Baby No. 3 will not displace Charlotte but fall in line behind her. That’s due to a new law introduced shortly after the Duke and Duchess of Cambridge married in 2011 that gave any daughter of a future U.K. monarch equal right to the throne. It took effect four years later. Its passage, approved by all 16 Commonwealth countries where Queen Elizabeth is head of state and the U.K. Parliament, upended a centuries-old succession law that said that the first-born son of a monarch would inherit the crown. Only if a monarch had no male heirs—as was the case for the Queen’s father George VI—could the throne be passed to a daughter.

“The idea that a younger son should become monarch instead of an elder daughter simply because he is a man…is at odds with the modern countries that we have become,” David Cameron, then the U.K. prime minster, said at the time of the law’s passage.

This story has been updated to reflect the birth of the royal baby.