The first system of formations would be taken from typical Germanic tactics, involving an army of mainly infantry. This composition would represent an invasion or conquering force rather than a typical Slavic rading force.
The main idea centers around the concept of war chiefs and their retinue of followers - an army would consist of 1-3 war chiefs or generals. Each war chief would contain a retinue ratio of 1 bodyguard/elite infantry unit per 2/3 missile/skirmisher infantry units and 3/4 spearmen/axemen/swordsmen units. Thus a war chief standard would include:
1 war chief general unit
2 bodyguard/elite infantry units
3 spearmen/axe/swordsmen units
2 missile/skirmisher units
The trio of war chiefs would form up side by side, thus 1 chief on the left, 1 on the right and the last cheif in the center, with the commanding cheiftain in the rear (the most senior war cheif in overall command). Each war chief would array his forces identically in seperate columns side by side:
xxx chieftain general
xxx xxx bodyguard/elite
xxx xxx xxx spear/ax/sword
xxx xxx missile/skirmishers
xxx cavalry
The general and elite would hit the enemy line first, with the spear/ax/sword units in support to push deeper or move around to hit the flanks. Cavalry kept in reserve to overrun broken foes.