The first overseas deployment of Canadian military forces occurred during the Second Boer War, when several units were raised to serve under British command. Similarly, when the United Kingdom entered into conflict with Germany in the First World War, Canadian troops were called to participate in European theatres. The Canadian Crown-in-Council then decided to send its forces into the Second World War, as well as the Korean War.
Is there an answer to this question (If it cannot be answered, say "unanswerable"): Who entered into conflict with the United Kingdom during the First World War?
unanswerable