"LLAN ILLTWRN, in the Cwmwd of Uwch Caeth, Cantref of Brenhinol (now called the Hundred of Dinas Powys), County of GLAMORGAN, South Wales: a Chapel, not in charge, annexed to the Rectory of St. Fagan's: Patron, The Earl of Plymouth: Chapel dedicated to St. Illtyd. The Resident Population of this Parish, in 1801, was 84. The Money raised by the Parish Rates, in 1803, was £61..0..3 It is 6 m. N.W. from Caerdiff. This Parish contains about 1000 statute acres of Land, all inclosed. The remains of the Monastery are now a Barn. This Chapelry is supposed to have been separated from the Parish of St. Fagan's, about the reign of Queen Elizabeth: it has a Register, and chooses its Warden, and makes its own Rates; but pays to the repairs of St. Fagan's Church and Bridge; and when the Rate for them is made, it pays the third Penny. The Duty of this Chapel is once a day, Morning and Evening alternately, and generally in the Welsh language.- "St. Iltutus founded a Monastery here, A. D. 508, and made it a place for Education in human Learning as well as Religion: so that many worthy Men are said to have been brought up here." - Tanner's Not. Mon. From: A Topographical Dictionary of The Dominion of Wales by Nicholas Carlisle, London, 1811.
"LLANILTERNE, or CHAPEL ILTERNE (LLANILLTEYRN), a parochial chapelry in the hundred of DINAS POWIS, county of GLAMORGAN, SOUTH WALES, on the road from Cardiff to Llantrissent, 6 miles (W. N. W.) from Cardiff, containing 149 inhabitants. It is stated to have been separated from the parish of St. Fagan about the reign of Queen Elizabeth; but the inhabitants still contribute one-third to the repairs of the church and bridge of that parish. The living is consolidated with the rectory of St. Fagan's, in the archdeaconry and diocese of Llandaf. The chapel, dedicated to St. Illtyd, is a very small building, with a curious inscription, not wholly legible, at the southwestern angle of the exterior wall, said to be to the memory of the wife of the renowned King Arthur. There is a place of worship for Independents. At Llanvairvawr, an ancient farm-house belonging to the Earl of Plymouth, lately destroyed by fire, are the ruins of a religious house, founded about the year 508, by St. Illtyd, as " a place for education in human learning, as well as religion :" the chapel is entire, and has been converted into a barn. The average annual expenditure for the support of the poor is £157. 13. " ( A Topographical Dictionary of Wales by Samuel Lewis 1833)