Charlemagne: Dark Ages in Europe (1998)

(from the introduction:)

Charlemagne is a game covering the rise of the Frankish Empire in the 8th-9th centuries AD under the leadership of Carl the Great - Carolus Magnus or Charlemagne. In this period, the Franks unified Western Europe and established the foundations for later Medieval civilization.

Charlemagne is a two-player game. The Empire player controls the forces of the Frankish Kingdom, its allies, and client states. The Tribal player controls the forces of various competing kingdoms and tribes. Players must use a combination of military strength and cunning to maintain and increase their power. The Franks have the advantage of unity and a central position. The Tribal player controls a shifting coalition of forces.