Dr Sam Willis traces the history of the weapons that have shaped Britain.

Castles: Britain's Fortified History' is a series by historian Sam Willis who traces the story of Britain's castles and their unique role in our history from art and literature.

　　Centuries before the world's oceans became a global trade highway, Chinese seafarers set sail to faraway lands to exchange commodities. Now, Historian Sam Willis retraces the golden era of maritime trade to uncover a legacy that culminated in one of the greatest armadas of all time, and discover parallels between the world then and now.