Empress Matilda (left) was the rightful heir to the throne of King Henry I, who died in 1135. But her cousin Stephen (right), seized the crown from her, setting off the two-decades-long civil war known as the “Anarchy.”(ART Collection/Alamy Stock Photo, National Portrait Gallery)
Some 20 miles downriver of Oxford and an arrow shot from the eastern bank of the Thames rise the limestone ruins of Wallingford Castle, a massive fortress built following the Norman invasion of England in 1066. L