Available after completing chapter 3 in campaign mode. An envoy will offer tributes (rewards) to you 3 times a day, with a cool-down time of 1 hour between each visit.
With each tribute from the envoy, you have a chance to gain two of the following: gold, soldiers, silver earrings, agate ring, special item (specific to the envoy)
You may use a tribute seal to gain additional rewards by tapping on the envoy.
There is also a 50% chance with each tribute that you will receive a maid, which you can use to increase the charm of a selected consort. Each maid will increase the charm of your consort by a varying amount.