The Sorcer part 1: The Fort at River's Bend

The Fort at River's Bend is a novel published by Jack Whyte, a Canadian novelist in 1999. Originally part of a single book, The Sorcerer, it was split for publishing purposes. The book encompasses the beginning of Arthur's education at a long abandoned Roman fort, where he is taught most of the skills needed to rule, and fight for, the people of Britain. The novel is part of The Comulud Chronicles, a series of books which devise the context in which the Arthurian legend could have been placed had it been historically founded.
From Publishers Weekly
Fearing for the life of his nephew, eight-year-old Arthur Pendragon, after an assassination attempt in their beloved Camulod, Caius Merlyn Brittanicus uproots the boy and sails with an intimate group of friends and warriors to Ravenglass, seeking sanctuary from King Derek. Though Ravenglass is supposed to be a peaceful port, danger continues to threaten and it is only through the quick thinking of the sharp-tongued, knife-wielding sorceress Shelagh that catastrophe and slaughter are averted. Derek, who now realizes the value of the allegiances Merlyn's party bring to his land, offers the Camulodians the use of an abandoned Roman fort that is easily defensible. The bulk of the novel involves the growth of Arthur from boyhood to adolescence at the fort. There he is taught the arts of being a soldier and a ruler, and magnificent training swords are forged in Excalibur's pattern from the metals of the Skystone. While danger still lurks around every corner, this is a peaceful time for Britain, so this installment of the saga (The Saxon Shore, etc.) focuses primarily on the military skills Arthur masters, as well as on the building and refurbishing of an old Roman fort. Whyte has again written a historical fiction filled with vibrant detail. Young Arthur is less absorbing a character than many of the others presented (being seemingly too saintly and prescient for his or any other world), but readers will revel in the impressively researched facts and in how Whyte makes the period come alive.