Great Invasions: The Dark Ages "350-1066 AD"

Take command of several of almost 80 playable nations throughout 700 years of history starting in 350 AD, and lead each of your historical nations from birth through growth, stability and decline. It will not be easy to expand or, indeed, survive across the centuries - but master the arts of diplomacy, war, economics, and administration and there will be no limit to your ambitions!

source - http://www.matrixgames.com/products/359/details/Great.Invasions

Relive the great moments of this tumultuous period thanks to our precise and ambitious recreation, that will allow you to meet over 150 nations and more than 30 religions and heresies, as well as thousands of historical characters.

375-632 : time of the initial barbarian onslaught on the decadent Roman empire, from the arrival of Huns till the birth of Islam, and including the Byzantine revival and reconquest of lost lands under Justinian.
632-843 : while the barbarian threat recedes in the West, the Muslim warriors burst out of the Arabian deserts. This is the age of Jihad, where the strength of Islam leads the Arabs to the almost complete conquest of the civilized world.
843-1066 : the last stage is that of the last wave of invasions, and particularly the Vikings attacks (culminating with the Battle of Hastings in 1066). That is also the time when Charlemagne’s empire crumbles and the rise of feudality, signalling the entry of Western Europe into the Middle Ages.

GREAT INVASIONS is historically faithful to politics, economy, diplomacy, religion and art of war in the Dark Ages.

source - http://shopuk.ageod.com/game-description-Grandes_Invasions-659238.html

Adapted as a board game called Invasions: Volume 1 350-650 AD