Before the Civil War, about 700 free blacks lived in small enclaves in northern Nashville while there were over 3,200 enslaved people of color in the city. By 1860, when the first rumblings of secession began to be heard across the South, antebellum Nashville was a prosperous city. The city's significance as a shipping port and rail center made it a desirable prize for competing military forces that wanted to control the region's important river and railroad transportation routes. In February 1862, Nashville became the first Confederate state capital to fall to Union troops, and the state was occupied by Union troops for the duration of the war. Then African-Americans from Middle Tennessee fled to contraband camps around military installations in Nashville's eastern, western, and southern borders. The Battle of Nashville (December 15–16, 1864) was a significant Union victory and perhaps the most decisive tactical victory gained by either side in the war; it was also the war's final major military action in which Tennessee regiments played a large part on both sides of the battle. Afterward, the Confederates conducted a war of attrition, making guerrilla raids and engaging in small skirmishes, with the Confederate forces in the Deep South almost constantly in retreat.