The Grianan of Aileach, a massive 23 metre wide stone ring fort, thought to be around 2,000 years old, was the seat of the O'Neill kings until its was sacked by the King of Munster Murtagh O'Brien in the 11th century in revenge for the destruction of Kincora. Saint Patrick is also said to have baptised the first O'Neill king, Owen, here in 450AD. The fort, which has interior terraces leading up to its parapet and inside passage chambers, is in a very good condition because it was renovated by Bishop of Derry, Dr Bernard in the 1870s. It commands strategic and scenic hilltop views over Loughs Swilly and Foyle.