St Cristiolus's Church, Llangristiolus is a medieval church near the village of Llangristiolus, in Anglesey, north Wales. The village, about from the building, takes its name from the church. Reputedly founded by St Cristiolus in 610, the present building dates from the 12th and 13th centuries. Alterations were made in the 16th century, when the large east window in Perpendicular style was added to the chancel – a window which has been described by one guide to the buildings of north Wales as "almost too big to fit" in the wall. Some restoration work took place in the mid-19th century, when further windows were added and the chancel largely rebuilt. The church is still in use for weekly Sunday services (in Welsh and English), as part of the Church in Wales, and is one of four churches in a combined parish. It is a Grade II* listed building, a national designation given to "particularly important buildings of more than special interest", in particular because of its age and the east window. The church contains a decorated font from the 12th century, as well as memorials from the 18th, 19th and 20th centuries. Richard Owen, a 19th-century Calvinistic Methodist minister from Llangristiolus, is buried in the graveyard. History and location St Cristiolus's Church is in central Anglesey, north Wales. It is situated just to the south of the A5 and A55 roads, on raised ground above Malltraeth Marsh. The modern village of Llangristiolus is about to the west of the church. The village takes its name from the church: the Welsh word originally meant "enclosure" and then "church", and "-gristiolus" is a modified form of the saint's name. The date of foundation of the first building on this site is unknown. Geraint Jones, in a 2006 guide to Anglesey churches, wrote that it is thought that St Cristiolus established a church here in 610. Cristiolus, a 7th-century saint about whom little detail is known, was a follower of St Cadfan, a Breton saint associated with the Christian community on Bardsey Island in Wales. Cristiolus is also credited with the foundation of the church in Eglwyswrw in modern-day Pembrokeshire, south Wales. He was the brother of St Rhystud, who established the church at Llanrhystud in mid-Wales. The present building dates from the 12th century; it is the only medieval building in the parish. During the 13th century, the chancel was extended, and