Beside the Ocean of time
George Mackay Brown1994

Thorfiin Ragnarson is the daydreaming son of a tenant farmer who avoids work and shcool despite the best efforts of family, friends and neighbours. Instead, the boy dreams up elaborate historical fantasies of himself as a Viking traveller, a freedom-fighter for Bonnie Prince Charlie and the colleague of a Falstaffian knight who participates in the Battle of Bannockburn. He is then hurled into the future as Thor, who returns to Orkney as an adult and recalls his internmant in a German POW Camp...