The subject's father was Valentine, his uncle was Colonel John Seymour, Governor of Maryland , and a brother named Tobias, a London merchant, was nominated to succeed his uncle as Royal Governor of Maryland. Bowles served in the Admiralty as a secretary from 6 March 1689 until 15 January 1690. Bowles is first mentioned in the "Military Entry Books" in January 1692, when he was appointed captain-lieutenant in the regiment of Colonel W. Selwyn, later the 2nd Queen's, then just arrived in Holland from Ireland. In July 1705 he succeeded Colonel Caulfield in command of a regiment of foot in Ireland, with which he went to Spain and served at the Siege of Barcelona.