Date published/released: 

1845

"'P.'s Correspondence' is an 1845 short story by the 19th century American writer Nathaniel Hawthorne, constituting a pioneering work of alternate history. Some consider it the very first such work in the English language (depending on whether or not Benjamin Disraeli's "Alroy" of 1833 is defined as being alternate history). In any case, it is certainly among the earliest works of this genre in any language and apparently the first to introduce some features which were to become an essential part of it." -Wikipedia