Queen Elizabeth II to Become Great Grandmother for First Time in December

Buckingham Palace announced Friday that the Queen's grandson, Peter Phillips and his Canadian wife, Autumn, are expecting their first child. The baby, due in December 2010, will be Queen Elizabeth's first great- grandchild. Peter, in 2008 was also the first of the Queen's grandchildren to marry. Queen Elizabeth is reportedly delighted at the prospect of becoming a Great Grandmother for the first time.

Peter Phillips, 32, is the oldest son of Mark Phillips and Princess Anne who is the Queens, second child and only daughter. Peter Phillips and his sister, Zara, have no royal title or duties, but Peter is 11^th in the line of succession to the English throne, behind Queen Elizabeth's children and their children.

Succession is based upon legitimacy, religion, and gender. Only legitimate children born to those in line to the throne are included in the succession (immediately below the parent). Roman Catholics are excluded from the line of succession and male children rank in preference to female children.

Although Princess Anne is Queen Elizabeth's second child, under succession rules male siblings place above female children in the line of succession regardless of age. Male siblings, however are ranked by age, with older male siblings appearing above younger male siblings in the line of succession.

As such, Princess Anne's children also fall below all their royal cousins on the line of succession to the throne.

The current line of succession to the English throne is:

1. Prince Charles - Twice married eldest son of Queen Elizabeth and Duke of Edinburgh.

2. Prince William - Prince Charles and Princess Diana's eldest son

3. Prince Henry (Harry) - Prince Charles and Princess Diana's second son

4. Prince Andrew - Third Child of Queen Elizabeth II and Duke of Edinburgh

5. Princess Beatrice - Eldest daughter of Prince Andrew and Sarah Ferguson, former Duchess of York

6. Princess Eugenie - Second daughter of Prince Andrew and Sarah Ferguson, former Duchess of York

7. Prince Edward - Youngest child of Queen Elizabeth II and Duke of Edinburgh

8. James Windsor - Son of Prince Edward

9. Lady Louise Windsor - Daughter of Prince Edward

10. Princess Anne - Queen Elizabeth II second child and only daughter

11. Peter Phillips - Eldest son of Mark Phillips and Princess Anne

12. Zara Phillips - Princess Anne and Mark Phillips second child

Peter Phillips child, once born will be placed 12^th in line to the English throne, behind his/her father, but before Aunty Zara. Similarly, each new child born into the Windsor line and placed above Peter Philips in the line of succession hierarchy will further increment the child's position in line of succession to the throne.

For example, should Prince William produce an heir to the throne, that child, will be placed third in line to the English throne, demoting each existing member in the hierarchy by one position.