[3] With the duties of caring for his father's estate, Caldwell was only able to attend the common schools of Logan and Christian Counties until age fourteen.

[3] After Albert Sidney Johnson's retreat from Bowling Green, Caldwell commanded the 9th Kentucky until relieved by Colonel Thomas H. Hunt on his return from New Orleans, Louisiana.

[3] At the Battle of Shiloh, Caldwell received several wounds, including a badly broken left arm.

[3] Because of this, the Board of Army Surgeons offered him a medical retirement, but he declined, rejoining his regiment in Dalton, Georgia, two weeks later.

[4] Due to ill health, he declined to be a candidate for reelection although he faced no Republican opposition for the seat.

[4] After his time in Congress, Caldwell did not return to his legal practice, but became president of the Logan County Bank.