Type: Knightly Infantry
Available to: Denmark
Trained at: Castle
Cost: 60 Food, 30 Florins, 1.5 population slots (as of 1.73)
Armor/Pierce Armor: 1/0
Special: +10 vs. infantry, +2 vs. militia lancers and buildings.
Upgrades to: Livgarde
Upgrade century: 15th
Upgrade costs: 1000 Food, 500 Florins
Attack: Forging, Iron Casting, Blast Furnace, Dannebroog (Danish Unique Technology), Swordsmanship
Armour: Scale Armour. Mail Armour, Plate Armour
Training time: Indenture
Unless the enemy makes great use of infantry, the Herreman can be avoided in the 14th century until the player can upgrade it to the Livgarde in 15th. Although it is slightly cheaper than a Man-at-Arms, it also has weaker stats and could at most be used as a stronger form of militia
The Herreman does have melee armor, and its +10 bonus is quite useful against infantry civs, especially civs strong in militia (Bavaria, Saxony) and pike civs (Flanders, Bohemia, Helvetia, Scotland) - they tear through infantry like hot knives through butter - but they're quite expensive, and as mentioned, they have to share the field with those awesome Danish militia and men-at-arms. In short, make a few, but don't flood them unless the enemy is massing infantry.
From the 11th century on, the Scandinavian kingdoms started integrating the military methods of other European realms, slowly abandoning their viking past. The former viking armies were replaced with more professional forces, including elite formations mirroring Western Europe's knights, capable of doing great damage to any opponent in battle.