Have you ever wondered why the Duchess of Cambridge isn't referred to as Princess Catherine or Princess Kate since she is married to Prince William?

Catherine Elizabeth Middleton grew up in Chapel Row, a village near Newbury, Berkshire, England. She grew up in an upper-middle class family with her father, Michael Middleton, a former flight dispatcher and her mother, Carole Goldsmith, a flight attendant. They went on to found Party Pieces, a mail-order private company that sells party supplies and decorations.

Michael had ties to British aristocracy and benefited financially from trust funds that had been established over 100 years ago.  

Kate studied art history in Scotland at the University of St. Andrews, where she met William in 2001.

"When I first met Kate I knew there was something very special about her," William said.

The couple became engaged in November 2010 and married in April 2011 at Westminster Abbey.

When she married William she received the title of Duchess of Cambridge, however her lesser known name is Princess William of Wales, as a woman marrying into the Royal family takes their husband's name.

So her full title is: Her Royal Highness Princess William, Duchess of Cambridge, Countess of Strathearn, Baroness Carrickfergu.

So why isn't she know as Princess, when Diana, William's mother was?

According to CNN Royal Expert Victoria Arbiter, the Duchess title is more important, which is why she uses it.

"While Catherine is absolutely a Princess, her correct title is "˜Her Royal Highness the Duchess of Cambridge. She wasn't born a blood Princess, so she is not a Princess in her own right. When she married William, she took on the rank of her husband, a royal Prince. However, referring to her as "˜Princess Kate' is simply incorrect."

Since Prince William is also a Duke, that is his more important title and Kate assumed it for herself as well.

So why was Diana a Princess?

Again, it came down to her husband. You can be a Prince in two different capacities. Firstly, as a head of the a Principality. Secondly, you might be a 'minor' or non-Sovereign, Royal.

Charles is a Prince twice over, as he was born one and he was made one (Prince of Wales) in 1969. The second title is more important of the two, so Diana took the title of Princess.

Source: Marie Claire / Huffington Post