The sham castle folly on Mow Cop was built by Randle Wilbraham of Rode Hall in 1754 as a summerhouse to which the family could ride for picnics. Its elevated position meant it could be seen from the mansion, some three miles away on the Cheshire side of the county boundary.
‘The fast lock’d tower where ivy loves to creep,
Seems like the remains of some old Castle Keep’
So wrote the little-known Yorkshire poet Robert Carrick Wildon, in contemplative mood, at The Ruin in around 1850. His poem ‘Lines suggested while sitting at the Ruins’ was recently discovered and you can read it all here http://www.friendsofstives.org.uk/history/the_ruins.php
The Ruin, as it is called on the earliest OS maps, was built by Benjamin Ferrand and is inscribed with his initials and the year 1796. Also known as Ferrand’s Folly, or Harden Grange Folly, there is no explanation for why it later became known as St David’s Ruin.