Sam Willis shows how the castle arrived as an instrument of invasion with the Normans but became a weapon with which unruly barons challenged the Crown.

Sam Willis tells the story of the English ruler who left the most indelible mark on the castle - the great Plantagenet king Edward I who turned it into an instrument of colonization.

Sam Willis explores how, by the Wars of the Roses, castles were under attack from a new threat - the cannon, but survived into the Tudor era only to find their whole purpose challenged.