Although the area around Grace Dieu has historical connections dating back to the Romans and beyond the Priory came into being around 1235-1241 as a house for Augustinian canonesses, and was dedicated to God, the Holy Trinity and St Mary and was founded by Rohese (Rose) de Verdon. Rose was a member of a landowning family with estates around Belton. Her father Nicholas de Verdon had been given the land around Snape by William Wastneis, lord of the manor of Osgathorpe, to add to his park at Belton. Rose endowed the priory with “all my manor of Belton… the park, warren and mills’ and with the Manor of Kirby in Kesteven, Lincolnshire. The charter of the foundress, confirmed by Bishop Grosseteste of Lincoln in 1241, describes the priory as “the church of the Holy Trinity of the Grace of God at Belton dedicated to God and St Mary”. This provided the priory with the epithet Gratia Dei or Grace Dieu by which it is still known. Rose was buried in the priory chapel, and later records state that an annual sum of 12d was set aside to maintain a light shining on the tomb. The tomb and effigy were later removed, possibly at the Dissolution, to the parish church of Belton, where it can still be see today.
The first prioress was Agnes de Gresley, who was replaced in 1243 by Mary de Stretton. There was some concern about the spiritual state and the material welfare of the house in its early days.
John Comyn, Earl of Buchan and the Lord of Whitwick added more land to the priory estates in 1306. This comprised 100 acres of waste (newly cleared land from the forest) at Whitwick and Shepshed, probably equivalent to the current park at Grace Dieu.
By 1377 the priory had 16 nuns, with a hospital for 12 poor people attached. The account book of Grace Dieu for 1414-1418 survives in the Public Record office. The accounts were kept by Dame Petronella and her assistant Dame Katherine Midleton and detail stock controls (including pigs and cows), rent levels for lands and buildings, and the sale of produce. Some of the rents were large, such as land in Belton valued at £21 17s 9d. Sale of fish from the mill at Belton brought in £6.
Although there were some problems around 1440-41 between the prioress and her coterie of favourites, and the community as a whole nothing further dramatic appears have happened until 1535.
Grace Dieu, like most English nunneries, was by no means wealthy, and in 1535 its net income was valued at around £92 per annum. In 1536, however, the King’s visitors of religious houses provided a significantly lower valuation of £72 13s 4d.
In 1536-37 because of the lower valuation the priory was a candidate for suppression as a lesser monastery but it was reprieved, however the reprieve was short lived and in 1538 the priory was dissolved.