“At the very mouth of the harbour there runneth out a narrow neck of land which presented unto the sailors a high turret erected by citizens of Ros when they were in a flourishing state that they might more safely enter into the river’s mouth”
Perched fortress-like over some of the most treacherous waters in Ireland, the lighthouse tower was built by the Marshals about 1207, perhaps after a design seen by William at Acre while crusades. The Welsh monks of Rinn Dubhain had kept a bonfire blazing to alert shipping for many countries. The Vikings, finding such activities useful, did not disturb them. The Norman lighthouse, virtually unchanged, functions to this day.