But out of sight, difficult to access, and in poor condition, it was abandoned in the late 1900s in favour of a newer, more conveniently located and comfortable church. Over the next 70 years, the old church would spiral into dereliction.
The old church of Llantrisant was supplanted by a new Victorian church a mile to the east in 1899. The old church struggled on, but after falling into serious disrepair became the first Welsh vestings with the Friends of Friendless Churches in 1978.
The church is mentioned in the Valuation of Norwich of 1254 as the Ecclesia de Llansann. The nave and chancel date from the 14th century. The south chapel, with its distinctive L-shaped form, was added in the 17th century.
The oldest item of church furniture is the font, from the late 12th or early 13th century. However, it is not original to this church – it was brought from the medieval church at Grove, Buckinghamshire, which it as converted to a house in the 1970s. The original font from Llantrisant church has been missing for several decades.
There are two highly sophisticated Baroque monuments, of 1669 and 1670 – so unexpected in a rustic setting.