The civil war that took place in America lasts from 1861 to 1864. It was a battle where only Americans participated. The whole reason why the war started was because of the topic of slavery.
It was the southern states, who owned slaves, were battling the northern states, who were against slavery and had recently abolished it.
Mikey has a secret relationship with Martha, (fodnote) which they are not allowed to be, because of Sterling Gage. Sterling Gage has forbidden them to be together because he wants to be with her. "His jealousy forbade to go with any other man." (fodnote) That is why he also raped her. (fodnote)
Mikey was in his younger days friends with Sterling Gage, but after Sterling Gage accused Mikey of stealing sugar and therefore got his father to beat the "eight-year-old" (fodnote) slave back then, their friendship ended. Mickey's desire for revenge, therefore, also began from that day on.