Prince Charles first enjoyed a tour of the castle, where he admired historic graffiti scratched into the stonework and viewed tapestries.
Prince Charles then climbed to the very top of the castle to take in the majestic views of Coningsby and Tattershall itself.
Maggie Everington, the visitor experience and volunteering manager at Tattershall Castle, said: “It is brilliant to have him here but also, as he is the president of the National Trust, it’s even more important that he has come to see what is a very important site and part of our portfolio.
“It’s been great to have him here as support for us and so we can tell him all the fantastic things we have been doing.”
On his arrival, Prince Charles was greeted by pupils from Highlees Academy, in Peterborough, who donned homemade crowns for the occasion.
One pupil said: “We gave him our letters, we wrote questions about what it is like to be a King and what it is like in Buckingham Palace.”
Another said: “It was amazing (to meet Prince Charles).”
Following his tour of the castle, Prince Charles visited the nearby Holy Trinity Church.
He met school children from Tattershall and members of the Bain Valley Group.
The Rev Sue Allison accompanied Prince Charles during his tour of the historic church.
Rev Allison said: “It was an absolute honour and pleasure to meet him and show him our wonderful church.
“It is a real honour to think he would want to come to our beautiful church.”
Pupils from Tattershall Primary presented Prince Charles with a homemade ‘bat box’ - paying homage to the hundreds of bats which call Holy Trinity Church their home.
Catherine Richardson, deputy head teacher at the school, said: “The children are very excited about meeting Prince Charles.”
• See more in this week’s Horncastle News.