Tyfrydog was a Christian from north-west Wales in the fifth or sixth century, who was later venerated as a saint. He is said to have established a church in Anglesey, and although no part of the original structure remains, the current church is still dedicated to him. A nearby standing stone is said to be the remains of a man who he punished for stealing a bible from the church.

St Tyfrydog's Church, Llandyfrydog is a small medieval church, in Llandyfrydog, Anglesey, north Wales. The date of establishment of a church on this site is unknown, but one 19th-century Anglesey historian says that it was about 450. The oldest parts of the present building are dated to about 1400, with the chancel dating from the late 15th or early 16th century. It is built from rough, small, squared stones, dressed with limestone. One of the windows on the south side is raised to illuminate the pulpit, a decision that in the eyes of one 19th-century commentator "disfigures the building."