Ontario-born historian Andrew Preston has captured the $25,000 Charles Taylor Prize for his book Sword of the Spirit, Shield of Faith: Religion in American War and Diplomacy.

The Canadian author, who currently teaches U.S. history and international relations history at Britain's Cambridge University, received the annual literary non-fiction honour at a midday ceremony in Toronto on Monday.

Andrew Preston called the Charles Taylor Prize 'a visionary award.' (CBC Books)

"I'm extremely honoured and flattered," Preston told the crowd after taking the stage to accept the honour, which he described as "a visionary award."

Preston's book explores American governments over the years and how religion has affected their foreign policy decisions — revealing that there has never been a true separation of church and state.

The Charles Taylor Prize toasts a book that "best combines a superb command of the English language, an elegance of style and a subtlety of thought and perception," according to organizers.

Monday's ceremony honoured the five finalists, with Governor General David Johnston and his wife Sharon among the guests in attendance. Johnston paid tribute to the authors, noting that writing non-fiction requires "dedication, patience and no small degree of fortitude."

This year's other finalists were:

• The Pursuit of Perfection: The Life of Celia Franca by Toronto writer Carol Bishop-Gwyn.
• Warlords: Borden, Mackenzie King and Canada's World Wars by Ottawa-based Tim Cook.
• Journey with No Maps: A Life of P.K. Page by Vancouver's Sandra Djwa.
• Leonardo and The Last Supper by Oxford, U.K.-based Ross King.

In addition to Preston's $25,000 prize, the remaining finalists will receive $2,000 each.

This year's jurors included broadcast executive Susanne Boyce, author Joseph Kertes and author, columnist and past Taylor Prize winner Richard Gwyn.

Established in the memory of Canadian writer and former newspaper correspondent Charles Taylor, the annual prize celebrates the author of a book that "demonstrates a superb command of the English language, an elegance of style and a subtlety of thought and perception."

Past winners have included Andrew Westoll, Carol Shields, Ian Brown and Charles Foran.

Noreen Taylor is founder and chair of the Charles Taylor Prize for literary non-fiction. (Tom Sandler/Charles Taylor Prize/Canadian Press )Tweets about "#charlestaylorprize"