Rare photos give a glimpse into when Prince Philip first met the Queen at Britannia Royal Naval College in 1939.
Among the historic photos released by the Ministry of Defence include the pair playing croquet together.
The photos, in black and white, show a time when then Prince Philip of Greece and Denmark was tasked to look after Princess Elizabeth after there was an outbreak of mumps.
A series of six tweets by the MoD says: "In 1939, HRH The Duke of Edinburgh met Her Majesty The Queen for the first time at Britannia Royal Naval College.
"The photos showcase the time that the then Prince Philip of Greece and Denmark was tasked to look after Princess Elizabeth after there was an outbreak of mumps which excused them from going to church.
"Among the rare photographs is one of Princess Elizabeth and Prince Philip playing croquet.
"These photographs were found in the private family album of the then Captain of the College Capt F Dalrymple-Hamilton. The photo album came into the Britannia Royal Naval College’s possession pre-1980.
"HRH The Duke of Edinburgh and Her Majesty The Queen were married for 73 years, with their wedding taking place in November 1947.
"The longest-serving British consort, HRH Prince Philip stepped down from the Royal Navy in 1952 to assist with royal duties."
The duke spent more than 70 years as the Queen's companion.
His support was unwavering as he stood by her side through each decade of her reign.
He was the longest-serving consort in British history - supporting the nation's longest-reigning monarch.
Their compatibility led to a long and successful marriage - despite their contrasting personalities - with Philip seen as adventurous and tempestuous, and the Queen as more passive, cautious and conventional.
Always one step behind Elizabeth, the duke let the monarch take centre stage, but accompanied her throughout the triumphs and trials of her role as head of state.
