This extraordinary reconstruction of a castle from the Middle Ages was built between 1820 and 1830 by architect Thomas Hopper for Georges Dawkins Pennant, the fabulously wealthy heir to a Penrhyn slate quarry fortune. Behind the façade of an impregnable Norman fortress is an extremely sumptuous country house, where English and Irish aristocrats would stay on the way to Holyhead port. The furniture collection is excellent and there are fine Old Masters in the dining room.