Charles Deane, the editor of Bradford’s “Historie” (ed.1865), makes, in indexing, the clerical error of referring to Coppin as the “master-gunner,” an error doubtless occasioned by the fact that in the text referred to, the words, “two of the masters-mates, Master Clarke and Master Coppin, the master-gunner,” etc., were run so near together that the mistake was readily made.

In “Mourt’s Relation” it appears that in the conferences that were held aboard the ship in Cape Cod harbor, as to the most desirable place for the colonists to locate, “Robert Coppin our pilot, made relation of a great navigable river and great harbor in the headland of the Bay, almost right over against Cape Cod, being a right line not much above eight leagues distant,” etc.  Mrs. Jane G. Austin asserts, though absolutely without warrant of any reliable authority, known tradition, or probability, that “Coppin’s harbor . . . afterward proved to be Cut River and the site of Marshfield,” but in another place she contradicts this by stating that it was “Jones River, Duxbury.”  As Coppin described his putative harbor, called “Thievish Harbor,” a “great navigable river and good harbor” were in close relation, which was never true of either the Jones River or “Cut River” localities, while any one familiar with the region knows that what Mrs. Austin knew as “Cut River” had no existence in the Pilgrims’ early days, but was the work of man, superseding a small river-mouth (Green Harbor River), which was so shallow as to have its exit closed by the sand-shift of a single storm.

Young, with almost equal recklessness, says:  “The other headland of the bay,” alluded to by Coppin, was Manomet Point, and the river was probably the North River in Scituate; but there are no “great navigable river and good harbor” in conjunction in the neighborhood of Manomet, or of the North River,—­the former having no river and the latter no harbor.  If Coppin had not declared that he had never seen the mouth of Plymouth harbor before ("mine eyes never saw this place before"), it might readily have been believed that Plymouth harbor was the “Thievish Harbor” of his description, so well do they correspond.

Goodwin, the brother of Mrs. Austin, quite at variance with his sister’s conclusions, states, with every probability confirming him, that the harbor Coppin sought “may have been Boston, Ipswich, Newburyport, or Portsmouth.”

As a result of his “relation” as to a desirable harbor, Coppin was made the “pilot” of the “third expedition,” which left the ship in the shallop, Wednesday, December 6, and, after varying disasters and a narrow escape from shipwreck—­through Coppin’s mistake—­landed Friday night after dark, in the storm, on the island previously mentioned, ever since called “Clarke’s Island,” at the mouth of Plymouth harbor.

Nothing further is known of Coppin except that he returned to England with the ship.  He has passed into history only as Robert Coppin, “the second mate” (or “pilot”) of the may-Flower.