Before you conduct your first warfare, you need to take a close look at all available units, their capabilities and intended use. Effective use of army will not only allow to win the combat, but also to minimize casualties among units. Fewer soldiers are lost in combat, lower costs you have for participation in war, and the higher could be warfare intensity.
There are only 12 various units. 3 units (Pushcart, Oxcart and Ship) are transport units. They are needed only to deliver resources and have no impact on the course of battle. The rest 9 units are designed to conduct warfare; we will enlarge upon this point.
At the start of the game, the main efforts of the players are focused on economic development, i.e. improvement of buildings, resource extraction, takeover of vacant castles, etc. However, subsequently, more attention is being paid to warfare. Eventually, any game comes down to confrontation between two largest unions on the server; therefore, it is impossible to win the game without knowing battle system.
Any combat consists of battle rounds. One round lasts 10 minutes. If at the end of the round there are 100 or more soldiers participating from each side (transport units are not taken into account), all the participants of the battle will have only 50% from the calculated casualties and they will move on to the next round.
In 2016, a new group of attacking units, Vikings, first appeared in the game. Their main distinctive feature was that under certain circumstances they could break protection bridges of enemies. Vikings managed to make a dramatic difference in outcome of many battles.
Each Viking (Berserker, Nordic Archer or Axe Rider) is efficient strictly against particular type of defending units. Thus, for example, Berserkers are more effective against enemy cavalry, Nordic Archers are highly efficient against infantry, and Axe Riders are best against artillery.