Is anyone aware of any other wars, civil wars, wars of invasion, etc., conducted by any other country(ies) for the abolition of slavery? I'm not talking about people who were "slaves to a system" or "slaves of conscience". I'm talking about the contractual ownership of people. Was the U.S. the only country to fight "a war to free the slaves". I am not saying "the cause" of the American Civil War/War Between the States was slavery. I'm asking if any other countries, groups, alliances, etc., ever fought a war for the abolition of a people, either internally (in their own country) or in another country?
If there were no other wars, fought for the emancipation of slaves. Please speculate on why you think only the U.S. was unable to end slavery, peacefully?
I don't want highly emotional responses, but thoughtful replies to this question.