The Stones of Green Knowe
Book 6 of 6 in the Green Knowe series by Lucy Boston.
Roger d’Aulneaux was the first child to live in Green Knowe (in AD 1120) and loved it with such pride that he longed to know it would endure. He finds his own magic that will take him forward to check on its safety hundreds of years ahead. He meets Toby, Linnet, Susan and Tolly who live it just as he does.