The King adapted the traditional state visit programme to accommodate Nigerian President Bola Ahmed Tinubu's Ramadan fast, omitting the customary formal lunch.
His Majesty is hosting the Nigerian leader and First Lady Oluremi Tinubu for a State Visit, with the Queen and the Prince and Princess of Wales in attendance.
The occasion represents a landmark diplomatic moment, marking Nigeria's first State Visit to Britain since 1989, when Queen Elizabeth II received military ruler General Ibrahim Babangida.
It also constitutes the first state visit by a Muslim head of state during Ramadan in nearly a century.
King Charles skips lunch to accommodate Muslim President of Nigeria
|GETTY
The two-day visit coincides with the final days of Ramadan, the Islamic holy month when observant Muslims abstain from food and drink between sunrise and sunset.
The last comparable occasion occurred in 1928, when King George V, Charles's great-grandfather, received Afghanistan's King Amanullah Khan during a state visit from March 13-15.
However, no records exist confirming whether the Afghan monarch observed the fast.
President Tinubu planned to break his fast privately at sunset on Wednesday evening before attending the state banquet with the King and Queen.
President Tinubu and King Charles inside Windsor Castle
|PA
The Prince and Princess of Wales welcomed President Tinubu and his wife at Fairmont Windsor Park spa hotel before accompanying them into the town centre for their meeting with the King and Queen.
Catherine chose a coat dress by Tolu Coker, a British-Nigerian designer, paired with earrings that once belonged to Diana, Princess of Wales.
The royal party travelled by carriage procession, with the King and President Tinubu riding in the Australian State Coach, escorted by the Household Cavalry Mounted Regiment.
Spectators lined the route through Windsor, cheering as the carriages passed. Approximately 200 members of the Renewed Hope Ambassadors-Diaspora attended, some travelling from mainland Europe, wearing specially made T-shirts featuring the royal and presidential couples.
The King and President Tinubu riding in the Australian State Coach
|REUTERS
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Nigerian First Lady Oluremi Tinubu, Queen Camilla, Nigerian President Bola Ahmed Tinubu and King Charles view items related to Nigeria from the Royal Collection exhibition
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The First Lady, known as Remi, is a Christian and ordained Pentecostal pastor. The Nigerian president's visit aims to bolster Britain's standing as a leading destination for African commerce.
The Department for Business and Trade announced that hundreds of jobs will be created as multiple Nigerian firms expand their UK operations.
During their time at Windsor Castle, the King joined President Tinubu and the First Lady in Vicars' Hall for meetings with organisations focused on interfaith dialogue.
The presidential couple are scheduled to depart Britain on Thursday evening, coinciding with the start of Eid al-Fitr, the Islamic festival marking Ramadan's conclusion.