A large collection of letters, maps and other papers that once belonged to Sir John Sherbrooke, the lieutenant-governor of Nova Scotia who conquered Maine for the British during the War of 1812, has sold for $573,000 at auction in London.

The winning bidder was Library and Archives Canada, and the future Canadian Museum of History. Including commission, the sale cost the federal government about $690,000.

The government said its acquisition is the largest known collection of War of 1812 documents.

The collection, which includes hand-drawn maps from the early 1800s that show major Canadian cities such as Halifax, Toronto and Montreal in their infancies, sold for almost twice what had been expected.

The collection also features a letter written by Sherbrooke to Maj.-Gen. Robert Ross congratulating his troops — composed of Canadian and British soldiers — for successfully burning down the White House in August 1814.

Sherbrooke went on to become governor general of British North America, and he gave his name to Sherbrooke, Que.

When he left Canada, Sherbrooke took his maps and papers back to Britain, where they had been sitting in three wooden boxes in family attics for nearly 200 years.  

"This is an archive that really charts Canadian history at a key point," said Matthew Haley, the head of manuscripts at Bonham's, the auction house that handled the sale. "It's about the birth of Canada as a nation and it’s unprecedented in its scope.

"It's a natural treasure really for Canada and Canadian history," he said.

Heritage Minister James Moore said the federal government is "proud to have acquired this one-of-a-kind original collection of our documentary heritage on behalf of all Canadians."

CBC's Ann MacMillan reported from London that the collection won't be heading back to Canada right away. Because the artifacts are considered to be of historic importance to Britain, a government body will have to grant an export licence. However, the auctioneers say that should not be a problem.