caldwell retired from the british army with the rank of major in 1774, remaining in quebec. he leased land that had belonged to governor george murray (british army officer) and built caldwell manor. the following year he served as a lieutenant-colonel with the militia during the defence of sainte-foy and was chosen to carry the dispatches reporting the victory to london. his military service earned him the king's praise, financial reward and a seat in the canadian parliament. in 1787 he was promoted to colonel of the quebec battalion of british militia, a rank he held until june 1794. described as 'a handsome soldier', caldwell was supposed to be the inspiration for the character colonel ed rivers in the novel "the history of emily montague", by frances brooke.