This was once the treasured possession of Sir Humfrey Gilbert, a flamboyant adventurer, who suffered such misfortune in the aftermath of his disastrous 1578 expedition to North America that even Queen Elizabeth I noted drily that he was a man of ‘not good hap’. But in the summer of 1582 after four years of virtual bankruptcy, Gilbert’s misfortunes appeared to be over. As he unrolled his newly acquired map, he allowed himself a rare and self-satisfied smile. It provided the most detailed record to date of America’s wild and barbarous shores, and contained a treasure-trove of priceless and hitherto unknown information. Such was Sir Humfrey’s pride in adding it to his collection that he reached for his quill and scratched on the words: ‘Humfray Gylbert, knight, his charte’.

This circular sheet of parchment depicted the entirety of North America as if viewed from high above the mid-Atlantic, and its inky squiggles confirmed what Gilbert had believed all along: that America was cut in two by a wide channel and that the interior of the continent was not land at all, but a vast inland sea.

More discerning observers might have expressed concern that the map’s provenance was uncertain and that it contained glaring and very obvious errors. One of the few parts of America that was well charted, the triangular island of Newfoundland, was shown as four separate lumps of rock, while the land’s eastern seaboard appeared to be little more than a topographical flight of fancy. But to Sir Humfrey, any such objection would have been a mere trifle. This map was to be the key to the crowning achievement of his life: a voyage to America, with the audacious goal of founding the first English colony on the shores of this mighty continent.