Webster 1913 is correct but I can hopefully provide a little more information.

The Decameron is a series of narrative poems written by the Italian poet Boccaccio sometime between 1349 and 1351. The "frame" story relates how ten Florentines, taking refuge from the plague, relate one tale each for ten days. This device and the stories themselves (many of which were traditional) was widely influential in late Medieval Europe: for example on Chaucer's Canterbury Tales.