The Hill of Slane has been an important location as far back as the mythical times of Ireland. In the verse of the bards called the Fir Bolg, it is said that High King Slaine mac Dela had been buried there and some believe that a second small mound on the hill is actually his burial mound.
Tradition says that Loegaire was so impressed by Patrick’s devotion that, despite his defiance (or perhaps because of it), he let him continue his missionary work in Ireland and appointed him Bishop of Slane.
This was the seat of the Flemings of Slane, who were barons of Slane and they lived on the hill until around the 15th or 16th century when they moved to a new castle near the Boyne River.
The Flemings were lords of Slane until the 17th century, when, Protestant lords were given Irish lands through what is now called the Williamite confiscations. The Conyngham’s who were a noble Scottish family, took over (some say purchased?) the Slane Castle and lands.