Also on the island is the 12th-century parish church of St Boniface (recently restored; open in summer) with a carved Norse "hogback" gravestone (probably also 12th century) in the churchyard. This stands on a substantial and largely unexcavated 9th century, or earlier, Pictish religious site – possibly including a bishop's residence. Remains of a heavily eroded broch can be seen on the shore. Early Christian carved stones, which may date from as early as the 7th century AD, found at this site are on display in Orkney Museum in the Tankerness House, Kirkwall and the National Museum of Scotland, Edinburgh. These may be the earliest evidence for Christianity to survive in the Northern Isles.