By Peter Muto ( December 15, 2017, 8:47 AM EST) -- There was no income tax in Canada until the Income War Tax Act came into effect on Sept. 20, 1917. The purpose of the Act was to finance the addition of 100,000 men into the Canadian armed forces in support of Canada’s efforts in First World War. The income tax rates of the United States were used as a model and the Act was thought to be a temporary measure....