The unit group of Mercenary Gunners is made up of siege cannons, which are either enabled with the Mercenaries technology or, in case of Scotland, "imported" from a different country. In contrast to domestic artillery, these gunners demand a high amount of florins for their services but are quickly prepared for war.
The following civilisations can hire Mercenary Gunners:
Florentine Gunner: France, Genoa,
Flemish Gunner: Burgundy, England, Guelders, Scotland
German Gunner: Poland, Teutonic Order