Buonconsiglio castle, Trento, Italy. It dates to about the year 1400. It's part of a series of paintings done by a Bohemian master called the "Cycle of the Months" showing the activities for each month.
As you can see, this is quite clearly a snowball fight! I wonder when the first snowball fight was? Did the Neanderthals chuck snowballs at each other?
Photo courtesy Terra Italia.