Fort Heiman was built almost entirely by slaves from Mississippi and Alabama, and slaves together with white laborers pressed into Confederate service helped build all three forts guarding the Tennessee and Cumberland Rivers. In the early years of the war, although the Confederate government refused to enlist slaves as soldiers, it pressed tens of thousands of them into army labor brigades to support the war effort. Usually men between 18 and 40 years old, hired from their owners, they loaded, transported, and unloaded supplies, washed uniforms, shined boots, mended clothes and tents, moved ordnance, cooked and served food, built and repaired roads and bridges, dug trenches and latrines, and constructed fortifications. Because this work with the armies was often hard and dangerous, many slave owners were reluctant to send their valuable property to the battle front for fear of loss or damage. After Forts Henry, Heiman, and Donelson were captured and occupied by Union forces, they became havens for refugee slaves seeking freedom and protection from their former owners and the Confederate army.