Caerleon is the historically important site of the Roman legionary fortress of Isca Augusta. St Cadoc's Church stands over the principia (headquarters), where the legionary standards were kept and statues of the Roman emperors venerated. The earliest surviving part of the church dates back to just after the kingdom of Glywysing was overrun by the Normans during the twelfth century and is thought to be the work of Hywel ap Iowerth, who was also the founder of the Cistercian Llantarnam Abbey.
The current church is in the Perpendicular style, which was fashionable in the fifteenth century. The tower, which stands at the southwest corner of the church, has a lower stage that was probably part of the original Norman church, incorporating twelfth/thirteenth century lancet windows. The church features a series of impressive stained-glass windows depicting the life of Christ and symbolising the faith and devotion of the saints associated with Caerleon.
References:The first written record of church in Danmark locality date back to the year 1291. Close to the church are several stones with a Christian text and cross inscribed. The oldest parts of the present red-brick church are from the 1300s. In the late 1400s the church was enlarged to the appearance it has today. The church has been modified both internally and externally several times, among other things after the fires in 1699 and 1889. There are lot of well-preserved mural paintings in the walls.