The King and Queen Consort have been visiting Yorkshire for a number of engagements.
They were welcomed to the ancient city of York to see the unveiling of a statue of the Queen – the first to be installed since her death.
The statue, at York Minster, will overlook a new town square, with Charles saying at the unveiling ceremony: “The late Queen was always vigilant for the welfare of her people during her life.
“Now her image will watch over what will become Queen Elizabeth Square for centuries to come.”
The 2m sculpture, weighing 1.1 tonnes and made from French limestone, was designed to celebrate the late Queen’s platinum jubilee and completed in August, the month before she died.
Charles barely flinched as a protester threw four eggs and him and his wife, Camilla, near to Micklegate Bar, a medieval gateway.
The King continued shaking hands with a member of the public as the eggs flew in his direction, only pausing briefly to look at the shells cracked on the ground.
As police were detaining the man, Charles continued with a traditional ceremony which sees the sovereign officially welcomed to the city of York by the Lord Mayor.
It was last carried out by the Queen, his mother, in 2012.
The King appeared unfazed as he did a walkabout and greeted some of the crowds.
Later, the King was cheered by crowds as he arrived in Doncaster, where he spent six minutes meeting well-wishers in an unplanned walkabout.
He and Camilla met officials in Mansion House, where the King officially conferred city status on Doncaster in a ceremony.
The pair then attended a reception with a menu which included free range egg and watercress sandwiches.
