The son of Francis Durant de Breval, D.D. who became prebendary of Westminster, Nov. 21 1674, which dignity he enjoyed till his death in February 1707. John was educated at Westminster school, whence he went to Trinity College, Cambridge, where took the degree of B.A. in 1700; was elected a fellow about 1702; and took his master's degree in 1704; but, upon some disagreement between him and Dr. Bentley, then master of that college, he quitted his Fellowship (or, more properly speaking, was expelled) April 5, 1708; and went into the army, then in Flanders, as an ensign. The ease with which he acquired the French and German languages, his great learning, his exquisite pencil, and genteel behaviour, were soon taken notice of by the Duke of Marlborough, who not only promoted him to the rank of Captain, but also employed him in divers negotiations with several German princes, which he executed with great integrity.