When it comes to an enduring romance in world history, Queen Elizabeth II and Prince Philip's relationship is surely one of the most memorable. Their love story began in the 1930s and continued for more than 70 years, making it the longest marriage in the history of the British royal family. Queen Elizabeth II described her husband on their golden wedding anniversary in 1997 as her constant strength and guide. Since their enduring love stood the test of time, becoming a legend, here are some of their cutest pictures.

Princess Elizabeth and Lieutenant Philip Mountbatten announced their engagement on July 9, 1947. She received a diamond and platinum engagement ring, which was designed by Prince Philip himself.

Their longest romance began in the 1930s, when 13-year-old Princess Elizabeth of England met the charming young Prince Philip of Greece. On 20 November 1947, Princess Elizabeth married Philip Mountbatten at Westminster Abbey in London, United Kingdom.

In December 1958, Her Majesty Queen Elizabeth II and Prince Philip, the Duke of Edinburgh, are sitting for a picture at their residence in Buckingham Palace.

The couple has four children. Prince Andrew, wearing red shorts and a blue jumper, pushes baby Prince Edward in a pram, while Queen Elizabeth II, Princess Anne, Prince Charles, and Prince Philip stand behind them.

In February 1966, Queen Elizabeth II of England and her husband the Duke of Edinburgh went on a tour of the Caribbean. They have big smiles in the pictures.

Throughout their lives, Her Majesty Queen Elizabeth II and Prince Philip visited Canada over 20 times. In the picture, the couple looks very happy on their trip to Canada.

On their 25th wedding anniversary in 1972, Queen Elizabeth and Prince Philip went through a basket of letters.

In June 1977, The Queen and Prince Philip were at Bow Churchyard with a replica of the Bow Bell in Bow Churchyard.

Queen Elizabeth II and the Duke of Edinburgh celebrated their Golden Wedding anniversary in 1997 at Broadlands, the place where they began the first part of their royal honeymoon in 1947. The Queen described her husband as her 'strength and stay'.

The Golden Jubilee of Elizabeth II was held on June 2, 2002, celebrating her 50 years of reign. The Queen, alongside her husband, attended the Golden Jubilee, where they received waves from the crowds.

In 2007, Queen Elizabeth II and Prince Philip celebrated their Diamond Wedding anniversary at Broadlands, the same place they spent their wedding night. They recreated the photos from their 1947 wedding.

Queen Elizabeth II and her husband reviewed the Pikemen Musketeers of the Honourable Artillery at Armoury House in 2010.

On April 29, 2011, Queen Elizabeth II and Prince Philip attended their grandson Prince William's wedding to Kate Middleton at Westminster Abbey in London, England, the same venue where they exchanged their vows.

During the Queen Elizabeth II Diamond Jubilee Tour of the UK on March 23, 2012, Queen Elizabeth II and Prince Philip, Duke of Edinburgh, listened to a speech as they visited the Manchester Royal Eye Hospital and St Mary's Hospital in Manchester.

As part of their official visit to Germany, the 89-year-old monarch and her husband, 94-year-old Prince Philip, embark on a mini boat cruise on the Spree River in Berlin.

The longest-serving British monarch in history, Queen Elizabeth II, and her family celebrated her official 90th birthday on June 12, 2016. In the picture, Her Majesty and Prince Philip are seen travelling by vintage carriage and waving to guests in London.

Her Majesty Queen Elizabeth II, alongside Prince Philip and the entire royal family, graced the 'Trooping The Colour' parade on June 17, 2017, in London.

Queen Elizabeth has been a fan of the Braemar Royal Highland Gathering since she was a child, the sports tournament held since 1832. On September 2, 2017, Her Majesty and Prince Philip enjoyed themselves at the Braemar games in Scotland.

Queen Elizabeth II and Prince Philip, Duke of Edinburgh attend Sunday Service at St Peter and St Paul Church in West Newton on February 4, 2018 in King's Lynn, United Kingdom.