A free app for Android, by Vojtech Jesatko.

This strategy game is based on the Middle Ages, a period of history that began from the fall of the Roman Empire to the Renaissance period. 

Castle Builder Medieval – an idle strategy game where you have to build your own medieval castle, explore the surrounding lands, gather resources, and fight off enemies in epic battles.

The player will begin as a new Lord in the Middle Ages. As the player progresses through the game, he will gain the ability to build up his own castle, with the ability to expand and strengthen the walls, as well as build up the castle’s towers, and other buildings.