Age of Empires II: Definitive Edition

Very simple to get and can be done with your first tax allowance.

At the amphitheatre in Constantinople, you have the option to host a chariot race for 400 gold and can ‘bet’ on one of four teams to win to get a boost to your legitimacy. You do this by selecting the building and choosing a chariot in the same way you would research or train a unit.

Just save before making your selection and reload if you don’t win. You can save this for later too if your legitimacy starts dropping too low.