It was washed up on the rocks below the cliffs of Rothiesholm in 1808 and if it was a basking shark then it was fifteen feet longer than anything ever recorded. And you can see a small piece of it in the summer exhibition, Sea Stories, in the Stromness Museum, made available by the National Library of Scotland from the John Murray Archive. With the exhibit you can read the accompanying letter to Lady Byron.

Dr Howie Firth tells the story of the sea creature and the work of Dr Yvonne Simpson in opening up clues to the mystery – and the possible literary consequences as well, for Byron received the remnant of the Stronsay creature just a few months before he set off for Geneva and the gloom of 1816, ‘The Year Without a Summer’. His house guests there were the poet Percy Shelley and his future wife Mary Wollstonecraft Godwin, who would in that dark summer – the result of the eruption of Mount Tambora in Indonesia – write the story of a monster and its creator, Baron Frankenstein.

And for science, he says, even if further research confirms that the Stronsay creature was a type of basking shark, some of the other sightings of sea creatures in waters around Orkney and Shetland may point to something even more strange.

“With this resolution I traversed the northern highlands, and fixed on one of the remotest of the Orkneys as the scene of my labours.  It was a place fitted for such work, being hardly more than a rock, whose high sides were continually beaten upon by the waves. “ – Mary Wollstonecraft Shelley, Frankenstein