Before the missionaries came to the Slavic lands to start writing down the known history, there was the Age of Mythos:
Forests, valleys and fields are full of creatures from Slavic beliefs. Even though they may look like monsters, you don't have to fight them all. Make proper offerings to them and you will gain powerful allies.
Give your workers a roof over their heads and a good supper and they will build a thriving settlement for you. Do not disappoint your subjects, because dissatisfied people may leave you.
A long spear and a sharp sword will always be useful - your settlement is threatened by monsters, other tribes, Vikings or even demons from distant lands.
Follow Slavic traditions to earn points that you may spend on special blessings from the gods - the warlike Perun, the generous Mokosh and the mysterious Veles.