I have painted one more medieval artillery piece for my Kalmar Union War project.
The miniature are a Perry one form their WotR range.
The first account of mobile artillery in Sweden was during the Puke rebellion in 1436 the Swedish Marsk Karl Knutsson, House of Bonde are told to have had a couple of "Kärrebössor" (cartgun) with them to use against the rebells.
Later in his career, now King, Karl Knutsson, House of Bonde in 1452 invaded Scania during a war with Denmark, according to the Karl´s Chronicles the Swedish army brought 20 "Kärrebössor" (cartgun) with them, and an army of 100 000 men...that part might be a bit exaggerated 10 000 might be mor in line with the truth...but the winner dictates the history expecially as the Karl´s Chronicles was written by order of the King himself...
In 1464 the Danes was besten by the Swedish rebells under command of the Linköping Bishop Kettil Karlsson, House of Vasa at the battle at Haraker. It is told that the Swedish rebells used artillery to defeat the Danes and at least one cannon ball have been found in the area of the battle.