[10] The main abbey building was Grade II* listed on 6 June 1962 "as an early and very elaborate Tudor revival country house.

"[9] Llantarnam Abbey's first historical study of note was researched by Joseph Bradney in his multi-volume A History of Monmouthshire from the Coming of the Normans into Wales down to the Present Time.

A lot of his work concentrated on the post medieval period including the pedigrees and heraldic coats of arms concerning the major families connected to the abbey.

The work is still used as a primary source by the Gwent Glamorgan Archaeological Trust when researching planning decisions on land associated with the abbey and its granges.

Compiled into a single volume, this culminates in an account which is probably the most complete history of the abbey that embraces an overall European Cistercian perspective.

Although Mahoney's study takes into account the Welsh political problems that were associated with Llantarnam through its initial patronage, it also addresses the overall British situation that arose through the dissolution of the monasteries.

[20] In contrast, research by Madeleine Gray has used a multi-disciplinary approach predominantly concentrating on the outlying granges on Mynydd Maen, Mynyddislwyn and the Rhondda valley.

This included experimental archaeology, which retraced a long and arduous pilgrimage route from Llantarnam Abbey, through the granges of St Dials and Llandderfel, before arriving at Penrhys in the Rhondda;[21] A post medieval survey of Henry the Earl of Pembroke's manor of Mynyddislwyn which includes many aspects of medieval land use deducted from the survey.

[27] Morgan[28] suggests Emsanternon as a mixture of both Bradney's and Osbourne and Hobbs understanding where Ynys is elevated to a ‘raised area in a water-meadow’, while Teyrnon is reduced to Teyrn meaning ‘prince’.

Morgan points out that it was not until 1272 that the Latinised Lanterna was instructed to be used in the official lists by the Cistercian General Chapter rather than Vallium which had been recorded in 1244.