* The year the *Decameron*, containing the story of "The Plague," was first published in English? The first English translation of the *Decameron* was published in 1620.
* The year a novel called *The Plague* was first published in English? There are many books with the title "The Plague," including Albert Camus's famous novel *The Plague*, which was first published in English in 1948.
Please clarify your question for a more specific answer.