North Stack North Stack North Stack (Welsh: Ynys Arw, meaning "rugged island") is a small island situated just off Holy Island on the north-west coast of Anglesey. North Stack can also refer to the headland opposite the island. This is the site of a redundant fog warning station, comprising a number of buildings, including the Trinity House Magazine, built in 1861, where shells for the warning cannon were stored. These buildings now house a bird watching observatory, giving a view of South Stack lighthouse across Gogarth Bay, and the studio of artist Philippa Jacobs. The Precambrian quartzite cliffs of this headland, including
Anglesey of Gwynedd. Apart from a devastating Danish raid in 853 it remained the capital until the 13th century, when improvements to the English navy made the location indefensible. Anglesey was also briefly the most southern possession of the Norwegian Empire. After the Irish, the island was invaded by Vikings — some of these raids were noted in famous sagas (see Menai Strait History) — and by Saxons, and Normans, before falling to Edward I of England in the 13th century. Anglesey (together with Holy Island) is one of the thirteen historic counties of Wales. In medieval times, before the conquest