Church of St Lawrence was built at the end of the 13th or the beginning of the 14th century. From this period the nave and the chancel come from, it is possible that the northern sacristy was also established at that time. In the fifteenth century, the southern porch and the tower on the western side were added. The church was restored in 1844 and in the years 1895-1898, when the spiral stairs of the tower were blocked, and a new entrance was placed in the western wall. Also, the nave was considerably rebuilt, among others a wall was inserted between the transept and the nave and the presbytery.
The church was built of limestone rubble. In the Middle Ages, it consisted of a four-bay, rectangular nave without a chancel separated externally, a southern porch with barrel vault, and a three-story western tower. It was crowned with a very high parapet on protruding corbels and a battlement. On the south side, it received a turret with a staircase, which, together with the parapet and the eastern window, was added in the 16th century. The ground floor of the tower was opened to the nave, while its upper storey was heated by a fireplace in early modern times. The tower was also a clear landmark for the ships passing in the area. The northern transept of uncertain dating, possible originally a side aisle running from east to west, also served as a sacristy.
Salter M., The old parish churches of South-West Wales, Wolverhampton 2003.
Website coflein.gov.uk, St Lawrence’s church, Marros.