Ideologically, the Confederacy claimed that the system of slavery in the South was superior to the class divisions of the North, because while the South devolved all its degrading labor onto what it saw as an inferior race, the black slaves, the North did so to its own "brothers in blood", the white working class. This the leaders and intellectuals of the Confederacy called "mudsill" democracy, and lauded the superiority of the pure-blooded Southern slave-owning "cavaliers" – who were worth five Northerners in a fight – over the sullied Anglo-Saxon upper class of the North. For its part, some of the military leaders of the North, especially Generals Ulysses S. Grant and William Tecumseh Sherman, recognized that their fight was not only to liberate slaves, but also the poor white Southerners who were oppressed by the system of slavery. Thus they took steps to exploit the class divisions between the "white trash" population and plantation owners. An Army chaplain wrote in a letter to his wife after the Union siege of Petersburg, Virginia that winning the war would not only result in the end of American slavery, but would also increase opportunities for "poor white trash." He said that the war would "knock off the shackles of millions of poor whites, whose bondage was really worse than that African." In these respects, the Civil War was in large part a class war.