In the later Middle Ages the number of monks ranged from 12 to 18. Generally one was away, heading Morville Priory, a dependent monastic cell between Bridgnorth and Much Wenlock. In addition to the canonical hours there was regular celebration of Mass in the growing number of chantries and other chapels. The chapel of St Mary, behind the High Altar, contained the tomb of Earl Roger and was endowed well from the early 13th century. A monk was appointed as its warden and it was initially used to celebrate Mass for visiting dignitaries. In 1343-4 a chantry was established there for the soul of Ralph of Shrewsbury, the Bishop of Bath and Wells, funded from the revenues of Boreton. Another chantry was endowed for John Burley in 1414, and shortly afterwards Henry V decided to establish a chantry in honour of St Winifred but, this had to wait until much later.