Foreign enlistment in the American Civil War
Foreign enlistment in the American Civil War (1861–1865) reflected the conflict's international significance among both governments and their citizenry. Diplomatic and popular interest were aroused by the United States' status as a nascent power and by the war's central cause being the globally divisive issue of slavery.
Source: Wikipedia — Foreign enlistment in the American Civil War (CC BY-SA 4.0)