borden's military career began in 1893, when he entered the king's canadian hussars. in 1897, as a member of queen victoria's diamond jubilee contingent he received the jubilee medal. by 1899 he rose to major in command of this corps. at the outbreak of the second boer war borden received a commission as lieutenant with the 1st battalion, canadian mounted rifles (which shortly after his death became known as the royal canadian dragoons (special service force)) and allotted to the 1st battalion, "b" squadron as officer commanding the 4th troop. he was brought to the attention of field marshal lord roberts', the british commander-in-chief in south africa, for repeatedly swimming with richard turner across the vet river at coetzee's drift, to draw the fire of the boers who were dug in on the north bank (5 may 1900).