why were slaves so important to the Confederacy war effort, especially when they did not fight in the war?

Slave labor maintained the economy.

Explanation:

And if they did not fight in the war, the slaves continued to work on the cotton plantations. It was the main raw material and "heart" of the Confederate economy. War is an extremely expensive investment, and during the civil war, the confederation was still funded from a primary economic source.

after the roman empire, the catholic church began to unify by taking on many duties of a government.

deflation   hope this