Paul Gross wrote and directed this film, and its closing song "After the War." His grandfather, Michael Joseph Dunne, a WWI vet, once confessed to a young Gross about bayoneting a young lad in the forehead. Gross later said on Dunne's deathbed he was muttering for forgiveness and he was the only one who knew what was being talked about.
At the time of release, the most expensive Canadian film ever produced costing $20 million in 2008 Canadian dollars.
Part of the funding came from the government of Alberta, which is also where it was filmed.
When filming the Battle of Passchendaele, Paul Gross was very meticulous about maintaining historical accuracy. He would keep various photos of the real battlefield and compare them with how the set looked.
The scene at the beginning of the battle of Passchendaele, in which Canadian soldiers walk on wooden planks between the wet trenches, is virtually identical to a famous picture of the battlefield taken by Australian photographer Frank Hurley on October 29th, 1917.