Blackrock 'Castle' was built by the Corporation in the earlier part of the 19th century. The original 'Castle' is indicated as having been a fort, erected by Lord Deputy Mountjoy in 1604 as much to defend himself against the citizens of Cork - who had showed rebellious inclinations the year before when they refused to acknowledge King James I as their new monarch following the unlamented death of Queen Elizabeth - as against the threat of a new Spanish invasion. In fact, there was already a castle or fort on the site which Mountjoy merely renovated and put in a more defensible position. This is supported by a document which petitioned the Queen in 1585 stating that Cork had a fort called Blackrock' which the citizens maintain with artillery to resist pirates and other invaders.' This building had a beacon light from a turf fire to guide shipping. In 1722 the old tower was destroyed by fire and a new one built by the citizens. The second building was also destroyed by a fire in 1827, and was again rebuilt by the city fathers at a cost of about 1,000 pounds.