Darron --

During the first year of the war, volunteer organizations offered their services to the governor, who then commissioned officers and accepted them in state service. Pay was usually reckoned from the date of acceptance, or sometimes the date the company received marching orders.

Once enough companies assembled in camp to organize a regiment or battalion, the governor then offered their services to the Confederate Secretary of War. Ordinarily state offers were accepted as a matter of form, and the Adjutant and Inspector General issued commissions to field and staff officers as submitted.

Numerical designations were issued by the A&IGO.

I'm not an expert on Tennessee units, but it appears that three regiments offered their services directly to the War Department in Richmond. These were accepted under the designation, P.A.C.S., or Provisional Army of the Confederate States. Sometimes you see the title, 1st Tennessee Confederate, which sounds a little redundant.

If someone else has a better explanation, I'd like to hear it.