Players can set a home kingdom by doing the following:
- From the world map, select the kingdom to be made home kingdom
- Press the 'Kingdom' button
- Select the 'Income' tab
- Press the button labeled 'Set this as your Home Kingdom' (for the one-time cost of 50 gold)
Players can set a new home kingdom as often as they want, the only restriction is the 50 gold cost.
Having a home kingdom gives you a few things - it generates 500 gold per day, doubles the tribute amount from the kingdom, and serves as a collection spot for all gold and tribute from all kingdoms. Additionally, a players home kingdom is where their defense team is (so the kingdom players invade when attacking you).