Book excerpt: Winner of Military History Monthly’s 2017 Book of the Year Award The Classis Britannica was the Roman regional fleet controlling and protecting the waters around the British Isles – in other words, Britain’s first-ever navy. For over 200 years it played a key role in the northern frontiers of the Roman Empire: it helped to establish the province of Britannia and assisted in Roman military campaigns, as well as controlling the continental coast through to the Rhine Delta. Outside of war, the Classis Britannica also offered vital support for the civilian infrastructure of Roman Britain, assisting in administration, carrying out major building and engineering projects, and running industry. Later, its mysterious disappearance in the mid-third century ad would contribute to Britain finally leaving the Empire 150 years later. In Sea Eagles of Empire, acclaimed historian Simon Elliott tells its story for the very first time.