Bardsey has been noted as a place of pilgrimage since the early years of Christianity, but there are signs of settlements on the island that date from earlier periods.

It became a focal point for the Celtic Christian Church, attracting devout monks, and it is believed that St Cadfan began building a monastery on the island in the sixth century.

Photograph by Permission of the National Library of Wales

The Abbey ruins are preserved today is the thirteenth century Augustinian Abbey of St. Mary’s and was in use until the dissolution of the Monasteries in 1537 after which Bardsey was left to the pirates and marauders until the establishment of a farming and fishing community in the mid-eighteenth century. The well-known reference to the island as the burial place of twenty thousand ‘saints’ dates from the early middle ages, when three pilgrimages to Bardsey were said to equal one to Rome.

The 30m lighthouse - the tallest square-towered lighthouse in the UK - was completed in 1821. At the beginning of the twentieth century, the population of the island was around 100, but in 1925 the ‘King’ of Enlli, Love Pritchard (the title was bestowed on successive community leaders by Lord Newborough), led most of the remaining inhabitants to the mainland to seek a less laborious way of life. Others began to settle there shortly afterwards, making a living mainly by farming and fishing.

The Bird Observatory was opened in 1953, and the island was bought by the Bardsey Island Trust in 1979.

Most of the houses that stand today were built by the landowner, Lord Newborough in the 1870s. The exception is Carreg Bach, which is probably typical of the houses before the nineteenth century building programme. At the same time, a new non-conformist chapel was built.