Despite its outwardly placid character, there was a time in Pembrokeshire's history when it was one of the most violent parts of Britain: the line of castles that runs from St Davids to Laugharne is a testament to the years of bitter struggle between the native Celts and the invading Norman, Anglo-Saxon and Flemish armies; the language and character of the county south of the Landsker line was changed forever by the conflicts of the 12th and 13th centuries.
With the exception of a few skirmishes during the Civil War, Pembrokeshire saw little military activity until the early 19th century, with the establishment, in 1814, of the Royal Naval Dockyard on the southern shore of the Milford Haven waterway. The need to protect the dockyard, as well as the broader requirement to deter any invading forces from establishing a bridgehead here, led to an increased army presence in Pembrokeshire; in the 20th century, the army and navy were joined by the Royal Air Force. Uniforms of all kinds became a familiar sight in the local dancehalls during the second world war, and the people of Neyland became accustomed to Sunderland and Catalina flying boats just overhead as they landed on, or took off from, the waters of the Haven.