Dublin Castle sits in the heart of old Dublin, on the highest point of land in the area, a ridge between the Liffey and the Poddle (which now flows underground). A sheltered harbour on the Poddle, Dubh Linn was the original Black Pool from which Dublin gets its name. It was probably the site of an ancient ringfort which guarded the harbour, and from the 930s a Viking settlement stood there. The Norman castle was founded in 1204 and the gates were once decorated with the decapitated heads of rebels and invaders. This gate is on Palace Street, the shortest in Dublin with only two addresses, one of which is the Sick and Indigent Roomkeepers Society, founded in 1790. Next door to it is the lovely Chez Max.