Wooden walls

This metaphor for ships obviously only lasted until ships ceased to be made from wood during the latter half of the 19th century. The metaphor is very ancient and the Greek general Themistocles in 480 BC interpreted the oracle of Delphi to mean the Greek ships when the oracle said, “Safe shall the wooden wall continue for thee and thy children.” The metaphor was of course taken up by the British and for very many years the Royal Navy’s wooden walls kept the British Empire safe.