1573-1609. Son of a Norwich clergyman, James Rosier graduated from Cambridge with a B.A. in 1592/3 and an M.A. in 1596. He became a Catholic in 1602. He was hired by Thomas Arundell, the prime backer of George Waymouth's voyage to New England in 1605 aboard the vessel Archangell, as recorder and naturalist.
Rosier kept a written record of the trip, including plants, animals, geographic features, and Native people. This was published in London soon after the voyagers returned, under the title: "A True Relation of the most prosperous voyage made this present yeere 1605, by Captain George Waymouth, in the Discovery of the land of Virginia: Where he discovered 60 miles up a most excellent River; together with a most fertile land. Written by James Rosier, a Gentleman employed in the voyage." Rosier may also have been to New England with Bartholomew Gosnold in 1602.
After returning to England, in 1608 he entered the English College in Rome and graduated as Father James Rosier, S.J., in 1609. Some accounts of his life indicate that Rosier the explorer was not the same person as the person who became a priest and have his dates as 1775-1635. More recent scholarship indicates that they were the same person.