Milles was born in Kent, probably at or near Ashford, around 1550, and died probably at Sandwich early in 1627. He was educated at Ashford and joined government service around 1570, and became a minor but important figure in the administration of Elizabethan England. He served on a number of diplomatic missions to France and Scotland, and was also employed as a spy in the pay of Walsingham. In 1579 he was made bailiff of Sandwich, and in 1585 became customer (chief customs officer) for Sandwich. This latter position was ostensibly a reward for services rendered, but in fact was a continuation of his intelligence-gathering work as he was able to intercept correspondence going to and from the continent. Among other posts, Milles was appointed a commissioner of prizes following Drake’s raid on Cadiz in 1596, secretary to the warden of the Cinque Ports in 1598, and keeper of Rochester Castle in the same year. He resigned his post as customer in 1623, probably because of ill health.
From The Biographical Dictionary of British Economists in Oxford Reference.