Llantilio Crossenny was a manor of the Bishops of Llandaff in the Middle Ages, and the site of their manor house can still be seen at Hen Gwrt. Their episcopal presence and the proximity of White Castle account for the 'exceptional scale' of the church. It is of Old Red Sandstone with a shingled spire. The tower and the nave are of the thirteenth century whilst the chancel was rebuilt in the fourteenth. The spire was added in the early eighteenth century and the whole was restored by John Prichard and John Pollard Seddon in 1856–7.
Either side of the East window of the chapel are two stone corbels which are said to represent Edward II. The interior also has a number of seventeenth and eighteenth century funerary monuments of high quality and stained glass by Charles Eamer Kempe.
References:The church of the former Franciscan monastery was built probably between 1515 and 1520. It is located in the UNESCO World Heritage Site of Old Rauma. The church stands by the small stream of Raumanjoki (Rauma river).
The exact age of the Church of the Holy Cross is unknown, but it was built to serve as the monastery church of the Rauma Franciscan Friary. The monastery had been established in the early 15th century and a wooden church was built on this location around the year 1420.
The Church of the Holy Cross served the monastery until 1538, when it was abandoned for a hundred years as the Franciscan friary was disbanded in the Swedish Reformation. The church was re-established as a Lutheran church in 1640, when the nearby Church of the Holy Trinity was destroyed by fire.
The choir of the two-aisle grey granite church features medieval murals and frescoes. The white steeple of the church was built in 1816 and has served as a landmark for seafarers.