Victory Chests can be earned every 24 hours by obtaining 15 stars in battle. These chests are filled with a wide range of rewards including food, gold, oil, and trade goods. The higher your league, the greater the rewards will be.  

The 24 hour timeframe starts with the first Star you earn in battle for the day. As soon as you earn a star, the next 24 hours are tied to the same Victory Chest. After receiving your chest, you’ll start working towards another so long as 24 hours have passed since obtaining the first star.