In 1779, Spain took sides in the American Revolution, attacking the English in ways that, incidentally, helped the American colonists. It also marked a point at which the Revolutionary War could reasonably be called an international affair. 

1783 is mentioned as an alternative year from this era - a year that is, of course, memorable to fans of the movie Highlander At one point the main character casually muses that "1783 was a very good year," and in a few lines makes it easy to remember what happened,then.

https://youtu.be/T8dVElW3chk