Answer:
The American Civil War.
Step-by-step explanation:
The American Civil war started when 11 Southern states seceded due to rising issues with Slavery. The remaining states, the Nothern states, formed the army called the Union Army to take back their land as seceding was illegal to the Union.
The following war that ensued lasted from 1861 to 1865. Resulting in many deaths for the freedom of black slaves.