King Charles and his wife Queen Camilla greeted crowds on Tuesday as they visited the Colosseum and Roman Forum on the second day of a state visit which is aimed at reinforcing close ties between Britain and Italy.
Charles, who is paying his 18th official visit to Italy, is on his first overseas trip this year as he continues to undergo treatment for cancer.
The British Red Arrows and Italian Frecce Tricolori aerobatic teams staged a rare joint flypast to mark the event, with Charles and Camilla watching the display alongside Italian President Sergio Mattarella at the Quirinale Palace.
"It is important to have good relations with European countries," said British tourist Jonathan Smith as he showed a picture on his telephone of the planes sweeping over the heart of Rome, multi-colored smoke flowing behind them.
Britain quit the European Union in 2020 and the royal visit is seen as part of an ongoing effort by London to ease the pain of the Brexit divorce with its old EU allies.
US President Donald Trump's move to impose sweeping tariffs on imports from around the world, while simultaneously questioning Washington's military commitment to Europe, has underscored the need for old European partners to continue to work together.
"I think it is great for the Anglo-Italian relationship, particularly given the current climate around the world," said British tourist John Forde near the Colosseum, when asked about the royal visit.
A group of children waved British flags as the royal couple walked towards the forum, from where they could enjoy a view of the Colosseum from a terrace.
Alberto Angela, a well-known Italian television personality and host of science and history shows, guided the king and queen during their brief visit to the forum, which served as the political, religious and commercial heart of ancient Rome.
"This is a place of big history... and having the queen and the king coming here makes sense," Angela told reporters after the royals left.
During their first full day in Rome, the king and queen also laid a wreath at the Tomb of the Unknown Soldier.
Charles is due to meet Italian Prime Minister Giorgia Meloni on Wednesday and then address a joint session of parliament -- the first British monarch to be given this honor.
Charles and Camilla also mark their 20th wedding anniversary on Wednesday and they will spend the evening at a state banquet hosted by Mattarella at his Quirinale residence.
