This inscribed stone is built into the external south wall of St Sulien's Church (NPRN 402554). Its Latin inscription, thought to date to date to the fifth/sixth century, reads 'Silbandus lies...'. It is superimposed by a simple linear Latin cross, thought to be seventh/ninth century in date, which obscures some of the earlier inscription. The stone does not derive from immediately local bedrock, the nearest source being some 6km distant. It has been suggested that the village's name, 'Silian' may derive from the name 'Silbandus' in the stone's inscription. Two other early Christian stones, Silian 2 (NPRN 275650) and Silian 3 (NPRN 419114) are both thought to be ninth/tenth century in date, and are housed within the church.

Sources include:
Thomas, C., 1994, And Shall These Mute Stones Speak?
Edwards, N., 2007, A Corpus of Early Medieval inscribed stones and Stone Sculpture in Wales

N Vousden, RCAHMW, 1 July 2013