The press Secretary to Britain's Queen Elizabeth, Ailsa Anderson, and footman Badar Azim, place a notice formally announcing the birth of a son to Prince William and Catherine, Duchess of Cambridge, in the forecourt of Buckingham Palace, in central London July 22, 2013 (Photo: Reuters)
The immediate line of succession to the British throne includes Queen Elizabeth II's four children and their offspring.
Prince William's baby son follows him in the order, overtaking William's younger brother Prince Harry at third in line to the throne.
1. PRINCE CHARLES, PRINCE OF WALES
Born 1948. Eldest son of Queen Elizabeth.
2. PRINCE WILLIAM, DUKE OF CAMBRIDGE
Born 1982. Charles' eldest son.
3. SON OF PRINCE WILLIAM, AS YET UNNAMED
4. PRINCE HENRY OF WALES
Born 1984. Charles' second son.
5. PRINCE ANDREW, DUKE OF YORK
Born 1960. Queen Elizabeth's second son.
6. PRINCESS BEATRICE OF YORK
Born 1988. Andrew's eldest daughter.
7. PRINCESS EUGENIE OF YORK
Born 1990. Andrew's second daughter.
8. PRINCE EDWARD, EARL OF WESSEX
Born 1964. Queen Elizabeth's third son.
9. JAMES, VISCOUNT SEVERN
Born 2007. Edward's son.
10. LADY LOUISE WINDSOR
Born 2003. Edward's daughter.
11. PRINCESS ANNE, PRINCESS ROYAL
Born 1950. Daughter of Queen Elizabeth.
12. PETER PHILLIPS
Born 1977. Anne's son.
13. SAVANNAH PHILLIPS
Born 2010. Phillips' eldest daughter.
14. ISLA PHILLIPS
Born 2012. Phillips' second daughter.
15. ZARA PHILLIPS
Born 1981. Anne's daughter.
Queen Elizabeth's descendants are followed by those of her late sister princess Margaret, her only sibling.
The offspring of their father king George VI's siblings then follow, with more than 60 living people descended from his father king George V, who died in 1936.
The monarchy's website lists 40 people, though some extensive counts reach around 2,000 people eligible to inherit.
Drawn up in an era of religious strife, the Act of Settlement 1701, which sets out the succession laws, states that only Protestant descendants of Sophia of Hanover, the mother of king George I, can accede to the throne. Roman Catholics and anyone marrying a Catholic are specifically excluded.
George Windsor, Earl of St Andrews, is the highest person currently excluded. A great-grandson of king George V, the 51-year-old would be 32nd in line, but married a Catholic.
The pending changes to the succession laws would remove the bar on those marrying Catholics and he would be restored to his place in the line.
His eldest son, 24-year-old Edward Windsor, Baron Downpatrick, confirmed in his mother's faith, is the highest excluded for being a Catholic.
Some counts list more than 5,000 living descendants, including Catholics.
The line is a vast tangle of nobility and ordinary, untitled descendants from all corners of Europe.
Several other European monarchs feature, led by King Harald V of Norway, who is within the first 100 in line.
Besides Britain, it is also the line of succession to the thrones of Antigua and Barbuda, Australia, The Bahamas, Barbados, Belize, Canada, Grenada, Jamaica, New Zealand, Papua New Guinea, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, Solomon Islands and Tuvalu.