Kate Middleton and Prince William celebrated their 6th wedding anniversary Saturday. The Duke and Duchess of Cambridge have experienced many milestones over the years and are parents to Prince George and Princess Charlotte.

As we celebrate the royal couple's big day, here is a timeline of their relationship.

2001 - 2005: Prince William and Kate Middleton's romance began at the University of St Andrews in Scotland where the two were studying art history. The prince later switched his course to geography. The two got close to each other in 2003 after Kate split from her previous boyfriend. Rumors about William's and Kate's alleged relationship made the rounds when the two were pictured skiing in Klosters together. In June 2005, speculation grew about their romance when they were pictured together much in love on the day of their graduation ceremony.

2006: After graduation, William and Kate went on to their new careers with the latter working as an accessories buyer for fashion chain Jigsaw, while the prince joining the Royal Military Academy at Sandhurst. Romance rumors sparked again when Kate made her most significant public appearance by turning up to watch William graduate as an Army officer.

April 2007: Reports surfaced that the rumored couple had split with each other but the breakup was for a brief time as the two reconciled in June. While remembering their time without each other, William told in an interview with ITN at the time of their engagement: "We were both very young … and we were both defining ourselves as such and being different characters, it was very much trying to find our way and we were growing up, it was just a bit of space, things like that and things worked out for the better."

April 2008: Kate made her first public appearance with William at a formal event as she watched him receive his wings as a qualified RAF pilot from the Prince of Wales at a ceremony in Cranwell. 

June 2010: Even though they didn't announce their relationship, they moved in together at a four-bedroom farmhouse in north Wales.

October 2010: Rumors about William and Kate's engagement surfaced when couple was spotted at a friend's wedding in Gloucestershire.

November 2010: Kate and William got engaged and the Clarence House announced that the prince proposed to his lady love while they were on holiday in Kenya. The duo greeted the press at St. James's Palace as she proudly wore Princess Diana's engagement ring. "Hopefully I'll take it in my stride," Kate said of her royal future at the time. "William's a great teacher, so he'll be able to help me along the way." Just days later, it was announced that the royal nuptials would take place on April 29, 2011.

February 2011: "This is a very special moment for Catherine and me," William said in a speech at a university as the first invitations to the royal wedding are sent out, the BBC reported at the time.

April 29, 2011: William and Kate got married at Westminster Abbey in London with the latter in a gorgeous Alexander McQueen wedding gown and her sister Pippa Middleton as her chief bridesmaid. The royal family celebrated with a reception at Buckingham Palace.

Kate Middleton Prince William wedding Britain's Prince William and his wife Catherine, Duchess of Cambridge, kiss as they stand next to bridesmaids Grace van Cutsem (L) and Margarita Armstrong-Jones (R) on the balcony at Buckingham Palace with other members of the Royal Family, after their wedding in Westminster Abbey, in central London April 29, 2011. Photo: Reuters

May 2011: Kate and William took their first vacation, their honeymoon, in the Seychelles.

June 2011: The newlyweds attended their first official engagement as a married couple at the ARK Gala Dinner at Kensington Palace.

July 2011: Kate and William took their first-ever royal tour as husband and wife, visiting Canada and California.

December 2012: The palace announced that the royal couple is expecting their first child together. 

July 2013:  Kate and William welcomed their first child, Prince George, at St. Mary's Hospital in London.

prince george Britain's Prince William and his wife Catherine, Duchess of Cambridge appear with their baby son, outside the Lindo Wing of St Mary's Hospital, in central London July 23, 2013. Photo: Reuters

October 2013: Prince George was baptized by the Archbishop of Canterbury in a private service at the Chapel Royal at St James's Palace in London.

Prince George, William and Kate Britain's Prince William carries his son Prince George, as he arrives with his wife Kate Middleton, the Duchess of Cambridge, for their son's christening at St James's Palace in London October 23, 2013. Photo: Reuters

April 2014: Prince George made his first royal tour when he joined his parents on their three-week Australia and New Zealand tour. 

September 2014: Kensington Palace confirmed that Kate was expecting her second child.

May 2015: Kate and William welcomed heir daughter, Charlotte Elizabeth Diana and introduced her to the world on the steps of the Lindo Wing of St Mary's Hospital, Paddington. 

kate middleton prince william princess charlotte Kate Middleton and Prince William are photographed with daughter Charlotte outside St. Mary's Hospital in London. Photo: Reuters/Suzanne Plunkett