The century begins with Abbot Henry Monyash still in post. It appears to have been a time of relative peace, with just a few administrative records made. In 1404 there was a dispute with the Prebendary of Sandiacre over tithes of land near Dale Abbey belonging to Sandiacre church. In 1411 Abbot Henry was mandated to visit Newhouse Abbey in Lincolnshire, St Mary’s parent house. In 1418 John Stanley was the vicar in Kirk Hallam, staying there until his death in 1428; he was succeeded by Robert Alastre, who died in 1442. In 1423 the Dean of Lincoln allowed the abbots of St Mary’s Abbey and Darley Abbey to appoint vicars for that turn to the livings of Matlock, Edlaston and Fenny Bentley. In 1425 Abbot Henry undertook to celebrate in chapter an obit for the sisters and brethren of Syon, and in 1425 he took the oath of allegiance of the new prior of Newstead.

Abbot number 16:  John Spondon
Abbot John Spondon ruled for 33 years from 1439 to 1472. In his time the roofs of the chancel and the lady chapel were altered; it was possibly he who had the Perpendicular clerestory windows in the nave built, but Abbot Richard de Nottingham is also a contender.       

Canon Richard de Nottingham (not the one who was to become abbot number 18) held the vicarage of Kirk Hallam from 1442 till 1458 and then of Ilkeston from 1458 till 1498. Canon John Monyash succeeded canon Richard at Kirk Hallam, and was still there in August 1497.

Again, this abbot’s tenure seems to have enjoyed a period of relative peace – which may go some way to account for the building programme. Just a few records remain. In 1450 Abbot John, along with the abbot of Welbeck, supervised the election at Welbeck Abbey of John Grene; it is not clear what John Grene was elected to, but it was probably the abbacy. Also in this year the apostate canon Ralphe Crowche was arrested. In 1457 William Fytell was pardoned by the king: he had refused to answer the abbot concerning a trespass. In 1462 Abbot John was a member of the court of appeal hearing the appeal against excommunication of Abbot Downham of Beauchief Abbey in South Yorkshire, who had led seven armed canons against the Visitor General; he was retired to the vicarage of Wymeswold. In September 1466 John Middleton was granted dispensation from a birth defect, he being the son of a priest and an unmarried woman; he became vicar at Heanor in 1477 and resigned from that post in 1485.