Rather than state the original (just to appease Jim) I'll say the earliest extant version refers to the ship 'Nottingham' Capt Saumarez, and the encounter/skirmish took place in The War of Jenkin's Ear in 1746, so my memory isn't way out from the previous posting. The family who still live on Guernsey and featured in a recent episode of 'Antiques Road Show' claim to have documents that indicate that Phil Saumarez wrote the ballad. The engagement between the 'Mars' and the 'Nottingham' is well documented 11 Oct 1746 and there are even paintings in the National Maritime Museum. There is a detailed account of it along with the painting on their website.

The ballad was later adapted to the exploits of many other ships by broadside hacks wanting to turn a quick shilling so we have versions referring to The Wasp, The London, The Dolphin, The Britannia, and even The Victory. The French ship also becomes other vessels such as The De La Marque, engaged by the London. No point in trying to sell a ballad about the Nottingham in 1780 when the ship no longer exists and has gone out of recent memory and the Dolphin or London are the current glamour boys.

Interestingly while the names of the ships vary considerably many versions retain some garbled form of the captain's name, Saumarez, (Somerswell/Summers/Summerville) naturally anglicised.