While Prince William and Kate Middleton are now seen as a model royal couple, but before they got married in 2011, it was quite interesting to note that the young couple had their fair of relationship challenges.

The challenge came in the form of a brief split in 2007 that up to this day, experts are still speculating on the cause.

According to royal editor Duncan Larcombe, William and Kate's break may have been influenced by Kate's family who felt like some of William's friends were mocking her for her background. While Kate does not come from a dirt poor family, she does not have royal connections like some of the Prince's friends, and a few of them have never quite accepted her as a fitting partner for their friend, Express UK reported.

According to Larcombe, some of William's friends would make sly references to Kate's mother being an air hostess whenever she was around.

A separate report from Daily Express, citing another royal expert, Vicky Ward revealed that during the duration of their relationship, Kate Middleton and her sister Pippa received plenty of insults from William's privileged friends who saw them as predators who wanted to marry above their station.

"There are plenty of snobbish insults from people who, despite Middleton's obvious attributes, believe that the monarchy needs to stop marrying 'out' of its class. One likened her and her younger sister, Pippa, 25, to the Bouvier sisters, with their obvious desire to 'marry well." Ward said.

Meanwhile, royal author Christopher Anderson posited that it was Camilla, Duchess of Cornwall who was responsible for the break up because she did not see Kate Middleton as a worthy of joining the royal family.

"She did not look at Kate as someone worthy of joining the Royal Family. Kate is the first working-class woman to be accepted into the Royal Family. She is descended from coal miners, and her mother was a flight attendant," he said.

The author said that in the end, it was Prince Charles, who finally gave his son the chance to decide whether he would make a commitment to Kate or leave her be.

Prince William popped the question to his lady love in 2010 while they were on holiday in Kenya and were wed in Westminster Abbey in 2011. The Duke and Duchess of Cambridge are now proud parents of Prince George, Princess Charlotte and Prince Louis.