Dynasties

To do this, you need to complete achievements of a certain kind (you can view their list in the game in the dynasty section). For example, dealing 1000 damage to enemies with a hero grants a certain number of dynasty points.

This is all perfectly clear. I just started the game not by playing through campaigns, but by playing through maps in "Single Player." I played through several maps and didn't earn any coins. I decided to tackle the campaigns, and now I have about six thousand coins, but there isn't much to buy with them (titles, portraits, and the only somewhat worthwhile thing, dynasty traits).