Thomas Bertram Costain, a prolific historian-novelist was born in Brantford, Ontario. He was the son of John Herbert Costain and Mary Schultz Costain; his father came from the Isle of Man. Costain attended public school in Brantford, and while still in high school, he wrote four novels, about which he claimed "none had earned ... more than a conventional letter of rejection."

He left school at seventeen when the acceptance and publication of a mystery story by the Brantford Courier led to his being offered a job as a five-dollar-a-week reporter. Later he moved on to Guelph, Ontario, where between the years 1908 and 1910 he was the editor of the Guelph Daily Mercury. While he was in Guelph, he met Ida Randolf Spraggue, having previously seen her in the part of Ruth in a production of The Pirates of Penzance . They were married on 10 September 1910 and eventually had two daughters...