Prince Charles: "Both my wife and I are overjoyed at the arrival of my first grandchild. It is an incredibly special moment for William and Catherine and we are so thrilled for them on the birth of their baby boy."
British Prime Minister David Cameron: "It is an important moment in the life of our nation but I suppose above all it's a wonderful moment for a warm and loving couple who got a brand new baby boy. It's been a remarkable few years for our royal family."
Prime Minister Stephen Harper "The arrival of the newest member of the Royal Family, a future Sovereign of Canada, is a highly anticipated moment for Canadians given the special and warm relationship that we share with our Royal Family. This new beginning reminds us of the remarkable and enduring relationship our country has enjoyed with generations of the Royal Family."
Thomas Mulcair, Official Opposition Leader: "The arrival of a newborn is a special time. All New Democrats join us in wishing good health and happiness to the baby, the new parents and the family."
U.S. President Barack Obama: "Michelle and I are so pleased to congratulate The Duke and Duchess of Cambridge on the joyous occasion of the birth of their first child. We wish them all the happiness and blessings parenthood brings. The child enters the world at a time of promise and opportunity for our two nations."
David Jones, Welsh Secretary: "This is a joyous event and I was delighted to hear of the safe birth of our nation's newest prince. The Duke and Duchess of Cambridge are already honorary Welsh people from living on Anglesey for so long and I know that the whole of Wales will join me in wishing them well in this new stage of their lives together."
Hugo Vickers, who has been writing and broadcasting on the royal family for more than 35 years: "This child will live an extraordinary life meeting some of the most famous and fascinating people, yet the royal family has learned to give its children as normal an upbringing as possible. This boy is born to be king but he may have a whole lifetime ahead of him first. He may reach 60 and not become monarch." To survive the inevitable attention, the new baby "will need to have a steadfast character and be aware of his place in history but not let it overwhelm him. Prince Charles always said there was never one moment when he realized he would be king, but that it was a gradual dawning on him that he had to behave better than everyone else."