This was a Florida company, entering Confederate service at Montgomery AL. It joined Col. Lucius M. Walker's regiment at Memphis TN, a command which the War Department mistakenly thought was from Tennessee. It was designated 40th Tennessee Regiment, later revised to the 5th Confederate Regiment after its multi-state composition was understood. After returning from prison, this company (formerly Co. "C", 40th Tennessee Regiment) became Co. "E", 42nd Tennessee Regt.

http://www.tngenweb.org/civilwar/csainf/csa42.html