Herefordshire is fortunate that in certain areas some records survive of religious establishments which existed well before 1066. There are a number of papers in the Club's Transactions which can be searched. Some older publications and original texts can be viewed online.
The Llandaff charters or Liber Landavensis
The 'Llandaff charters ' were put together about 1120 by the see of Llandaff in south Wales. They purport to be a collection of foundation charters and gifts to early churches or monasteries going back to the 6th century. Some of these foundations were in the area of south Herefordshire known nowadays as Archenfield. The bishop of Llandaff used the 'charters' to try to claim later churches (and their revenues) from the see of Hereford, in which he was ultimately unsuccessful. A transcription of the Liber Landavensis was published in 1840 by the Welsh MSS Society; there is a downloadable pdf version here. There is a later, better transcription from an early copy of the charters - The Book of Llan Dâv - published in 1893. Images of the charter book are available online from the National Library of Wales.
The charters have been analysed, notably by Wendy Davies in her books An Early Welsh Microcosm (1978) and The Llandaff Charters (1980). to show that in a large number there are genuine historical details. A paper by her on land measurements in the charters mentions a number of Herefordshire foundations.