High Middle Ages
Devils torture the damned in Hell (Abbey of Moissac, about 1050 AD)
In 1071 AD, the Byzantine Empire lost most of Anatolia (modern Turkey) to the Seljuk Turks at the Battle of Manzikert. About the same time, the Abbasids lost control of pieces of the Islamic Empire as well - to the Turks in the East, and to local rulers in Egypt, Spain and elsewhere. The collapse of these two ancient and strong empires forced European rulers to become more independent, and at the same time allowed Europe to become stronger.
An early sign of the new European power came as the Christians of Spain began to push out the Islamic rulers. Then in 962 AD, Otto the Great began to rebuild the Holy Roman Empire. In 1066, William the Conqueror expanded his kingdom to begin building an empire across England and France. Ten years later, the First Crusade succeeded in taking Jerusalem from the Fatimids. Italy was still struggling between being part of the Holy Roman Empire and being a lot of independent cities, but kingdoms were forming further east in Poland and Russia.
During the 1100s, the kings of France managed to get control of most of modern France. The cities of Europe grew rich enough to build the great cathedrals of the Middle Ages. But by the early 1200s, the High Middle Ages were already giving way to the Late Middle Ages as the Mongol Empire reshaped the politics of Eurasia.
To find out more about medieval history, check out these books from your local library or from Amazon:
The Holy Roman Empire and Charlemagne in World History, by Jeff Sypeck (1997). An exciting and accurate account of the formation of one of Europe's great empires.
Beyond the Myth: The Story of Joan of Arc , by Polly Brooks (1999). Accurate and thoughtful, with good illustrations and maps, though more a biography than a history.
Constantinople: The Forgotten Empire, by Isaac Asimov (1967). This book got many future Byzantinists started on their path. It's out of print, but you can get it used.
A Little History of the World, by E. H. Gombrich (2003). Written in 1935, the history is a little out of date, of course, but it is written to convey the facts of all of human history to young people, and I think it does a good job.