"Medieval Lands" offers sources for name and persona research

A great online source for documenting medieval genealogy is Charles Cawley's Medieval Lands, "the encyclopædia of territories in the medieval western world and the royal and noble families which ruled them."

The publication is hosted by the Foundation for Medieval Genealogy and includes the families of the rulers of 140 political entities in medieval Europe and western Asia for the years 500 through 1500.