910:

Map of South Eastern Europe
From the Atlas to Freeman's Historical Geography, edited by J.B. Bury, a map focusing on the political divisions of the Balkans and other portions of southeastern Europe, here at the Medieval History site.

920:

Map of the Byzantine Empire
Black and white map by Peter Dykhuis at ByzNet shows the borders of the empire.

950:

Ireland circa 950 AD: Viking Settlement
Clear map at the Ireland's History in Maps site is followed by useful info and a timetable of excerpts from the Annals.

966:

Piast Poland, 966 to 1370
A very clean black and white map depicting the boundaries of Poland at the death of Boleslaw the Brave in 1025 and during the reign of Kazimierz the Great, 1333-70. From the Library of Congress Country Study on Poland, online here at the Medieval History site.

980:

Map of Central Europe: 980
From the Atlas To Freeman's Historical Geography, edited by J.B. Bury, a map of the political divisions of Germany and Central Europe in the year 980, here at the Medieval History site.

1000:

Map of the Baltic Lands
A map depicting the lands bordering the Baltic Sea, including Russia, Scandinavia and Northern Europe. From the Atlas to Freeman's Historical Geography, online here at the Medieval History site.

Ireland circa 1000 AD: Age of Brian Boru
Clear map at the Ireland's History in Maps site is followed by useful info further reference.

Map of the Byzantine Empire
Black and white map by Peter Dykhuis at ByzNet shows the borders of the empire.

Map of South Eastern Europe
From the Atlas to Freeman's Historical Geography, edited by J.B. Bury, a map focusing on the political divisions of the Balkans and other portions of southeastern Europe, here at the Medieval History site.