 Once Confederate forces were routed in February, 1862, from Forts Henry and Donelson (on the Tennessee and Cumberland Rivers, respectively), Confederate commanders decided that any further effort in the defense of Nashville would be pointless, and they abandoned any attempt to keep Nashville behind their lines.It was almost immediately occupied by Union forces, who rapidly began preparations for its defense.The largest of the fortifications erected was Fort Negley, a star-shaped limestone block structure atop St.