During the Bronze Age, you will be able to compete in Multiplayer Battles. And with every Multiplayer battle that is won, you will be rewarded with a number of medals (depending on the amount of destruction). In contrast, losing a battle will cost you a few medals as well.
When you have accumulated 400 medals, you will will be enlisted in a League. There are six League levels available, with three levels in each level. The number of medals you have shall determine the level of League you will be enlisted to, so the more medals you have, then you will be part of an even higher level of League.
Being part of a League shall provide you with a Battle Bonus after every Multiplayer battle (this can be Food or Gold) and a Daily Dock Bonus, wherein you will be granted a shipment of a random Trade Goods or a Diamond. The number and amount of Trade Goods and Battle Bonus increases with the level of League you are part of.
League Levels
1. Copper - minimum of 400 medals
2. Silver - minimum of 800 medals
3. Gold - minimum of 1,400 medals
4. Kingdom - minimum of 2,000 medals
5. Empire - minimum of 2,600 medals
6. Dynasty - minimum of 3,200 medals