Doctor Who: The Time Meddler

The TARDIS lands on the Northumbrian coast, where new companion Steven discovers a Viking helmet and the Doctor deduces they must have arrived in the 11th century. Steven remains skeptical, especially when he and Vicki encounter what appears to be a Saxon hunter with a modern wristwatch. Investigating a monastery, the Doctor discovers further anachronisms. Who is the mysterious monk observing the time travelers' every move, and why is he so interested in the outcome of the Battle of Hastings?