From the publisher's website:

As a wise medieval ruler, you know that crafts are the key to a thriving city. The more your craftsmen work, the richer you become. Your task is to ensure that this process never stops, because all types of goods are inter-connected. Wheat has to be delivered to the mill so that foundry workers can enjoy freshly baked bread and cast the metal needed for the smith, which can then forge swords for the knights ... The aim is to build efficient production chains and, if possible, hinder your opponents.