Mercenaries refers to both a 13th-century Market technology and several units available to various civilizations. Mercenary units are generally able to be produced very quickly and cost only silver, however they demand alot to be hired. They are, again generally, available in the 15th century, and most of them require the Mercenaries technology.
To enable the training of mercenaries, you must first research Mercenaries. The technology is available from the 13th century at the Market, costs 200 food and 150 florins and is available to everyone. In addition to enabling mercenary units, it also enables Friesland to hire Ruiters and Bavaria and Saxony to hire Rhenish Knights. Note that mercenary units in many cases also require a policy decision to be researched. The exact mercenary units and their availability and skill will be listed later.
Some civs require their policy decisions to decide for mercenaries. For example, in Brittany you get to choose from either Mercenary Longbowmen or Genoese Crossbowmen, which is dependent on a policy decision. In Burgundy, you can employ Flemish pikemen or English longbowmen. A more interesting example is Saxony, where researching the Teutonic Order disables the Rhenish Knight, which is enabled by picking any other policy decision.
The Mercenaries ThemselvesEdit
Warriors could even then be considered as "Mercenaries" if an alliance existed between their sovereign and the one who hired them. Each mercenary unit is listed below, along with their availability and a brief description of their skills. Each unit has its own page as well.
Flemish Infantry (Burgundy (Requires Flemish Relations))Edit
Strong ranged pikeman.
Italian Infantry (Burgundy (Requires Italian Alliance), Hungary (Requires Angevin Dynasty))Edit
Tough medium-class infantry. Benefits from its high melee armour.
Scots Guard (France (Requires Auld Alliance))Edit
Fast trained and well equipped infantry.
Swiss Guard (France (Requires Eternal Peace))Edit
Elite Pikeman. Similar to the Swiss Pikeman.
Genoese Crossbowman (Brittany (Requires Francisation), France, Papal States (Requires Avignon Papacy)Edit
Strong, long-ranged crosbowman. Attack bonus vs. infantry and rams. French Genoese have +1 range.
Mercenary Longbowman (Brittany (Requires English Alliance), Burgundy (Requires English Alliance), Guelders, Papal States (Requires Roman Papacy))Edit
Accurate archer with high melee armor and no minumum range.
Short-ranged crossbowman. Attack bonus vs. infantry and rams. Available in 13th century.
Rhenish Knight (Bavaria (Requires Hausmacht), Liège (Requires Tribunal of the Palace), Saxony)Edit
Tough medium cavalry. Has armor vs. anticavalry units, it heals itself.
Note: The Teutonic Order cannot train this unit.
Condottiero (Italian civilisations)
Heavy cavalry similar to Rhenish Knights. High melee armour, heals itself; takes full damage from anticavalry units.
Cuman Auxiliary/Mongol Auxiliary (Austria (Requires Hausmacht), Naples (only Cuman Aux.; requires Durazzo Angevins), Hungary (Requires Arpad Dynasty))Edit
Fast cavalry archer that fires three shots per attack. The Mongol Auxiliary even fires 2-4 arrows per shot.
Guelders cavalryman with small anticavalry armor and attack bonus vs. infantry.
Note: Also the unique unit of Guelders. Friesland cannot upgrade to the Wapentuer.
Szekely Auxiliary (Hungary, Papal States (Requires Avignon Papacy))
Fast, light armoured lancer.
Long-range, cannon-equipped warship. Attack bonus vs. buildings and all land units (except peasants). English ships fire a different projectile, which travels quicker and more accurately.
Caravel/Likedeler (England, France, Friesland, Genoa, Saxony (Requires Hanseatic League))Edit
Stronger than Privateer, with longer range.
Florentine/Flemish/German Gunner (Burgundy, England, France, Genoa, Guelders, Poland, Scotland (Requires Flemish Imports), Teutonic Order)Edit
Ground-based cannon. Attack bonus vs. buildings, ships, siege weapons, and lancers. Has blast radius.