For most of World War I (1914-1918), Canada (under the British Empire) and Italy were allies during the war. During World War II (1939-1945), Canada and Italy were on opposing sides. On 10 June 1940, Canada declared war on Italy after Italian Prime Minister Benito Mussolini declared war on France and the United Kingdom. Canada partook in the Italian Campaign and the 1st Canadian Division and 1st Canadian Armoured Brigade participated in the invasion of Sicily, Moro River Campaign and in the Battle of Monte Cassino. Between 1940 and 1943, approximately 600 Italian-Canadian men were arrested and sent to internment camps as potentially dangerous enemy aliens. After the second world war ended, Canada and Italy established diplomatic relations in 1947.