Widelands is an open source (GPLed) game (work in progress) using SDL. It is in many ways similar to Settlers II by Bluebyte. So In Widelands, you are the regent of a small tribe. You start out with nothing but your headquarters, a kind of castle in which all your resources are stored. In the course of the game, you will build an ever growing settlement. Every member of your tribe will do his or her part to produce more resources - wood, food, iron, gold and more - to further this growth. But you are not alone in the world, and you will meet other tribes sooner or later. Some of them may be friendly and trade with you. However, if you want to rule the world, you will have to train soldiers and fight. The newest version of the game you find on LINK 2.
REQUIREMENTS: PENTIUM processor, 64 MB RAM, 8 MB VIDEO CARD