The mysteries are: who was the sailor, where was the island, and when was it “discovered”? But before all that: is this letter even real, or a fantasy?
A helpful, scrappy note that accompanies the letter, also unsigned and undated, makes a suggestion:
A letter written in Ld Cornbury’s hand but whether from a Mr. Ja[me]s Hyde son of the Chancellor who was a Sailor or who else does not appear
Lord Cornbury (d. 1753), who this note speculates is the copyist, was the son of Henry Hyde, 4th Earl of Clarendon (1st creation), and would have been the 5th Earl if he hadn’t died before his father, which made the Clarendon title temporarily extinct. I have to respectfully disagree with the note, however. I think the handwriting belongs to Thomas Villiers (1709-1786), who succeeded to the Clarendon title as the 1st Earl of Clarendon (2nd creation). If the identity of the copyist is not necessarily reliable then, what about the identity of the original author?
James Hyde (d. 1681) was the son of Edward Hyde, the original 1st Earl of Clarendon, who was Lord Chancellor to Charles II. James Hyde died aged only 31 and I haven’t yet been able to find evidence that he was a sailor but let’s assume that this is family knowledge and take the note-writer at his word. Early modern sailors started their careers extremely young, which means that if this really is a letter James Hyde wrote, it dates, roughly, to the 20 years between 1661 and 1681.
‘Honoured Father’, the letter begins: