[This image comes from Kylemore Abbey, and I am grateful to Mother Maire for permission to use it.]
It has been suggested that this is an earlier image of Lady Mary and that her habit and veil were over-painted at a later date. It does appear that some of her hair is visible on the right of the image.
In 1597, Lady Mary Percy’s Monastery of the Glorious Assumption of Our Blessed Lady became the first English convent founded in Brussels: it marked the re-establishment of monasticism for English women, and initiated a process which was to be followed by other establishments across Flanders and France. By 1675 there were fifteen enclosed English convents in Flanders alone and by the end of the century, more than thirteen hundred women had been professed there.
Lady Mary was the youngest daughter of Thomas Percy, seventh earl of Northumberland, and Anne Somerset, daughter of the Earl of Worcester. After the earl's execution at Tyburn on 22nd August 1572, as a result of his involvement in the Northern Rebellion , his wife fled abroad, remaining in Flanders as a pensioner of the King of Spain. Mary was educated in a succession of Belgian and French convents before returning to England at some time, for we find her living with one of her sisters, Lady Elisabeth Woodroffe, who had conformed to Protestantism, and here Mary suffered imprisonment for her religion. She finally settled in Brussels in the mid-1590s. Having decided to become a religious, Mary first tested the conventual life with the Augustinian Canonesses in Brussels and Louvain (the latter a house with many English members), but never made vows in either. However, these were not English convents and it was at this time she determined to establish a monastery specifically for Englishwomen.
Although not professed as a nun until 1600, she was persuaded by an English Jesuit, Fr. William Holt, to join with Dorothy and Gertrude Arundell to found the convent in Brussels dedicated to the Glorious Assumption of Our Blessed Lady. She told Fr. Holt:
Henceforth I promise to devout my fortune and all that I possess
towards founding a Benedictine monastery beyond the seas
where English hearts and voices shall join together in singing the
praises of God and praying for our unhappy country.
This foundation would follow the Rule of St Benedict, which, in the words of Abbess Neville, ‘had heertofore, most flourished, in that now hereticall kingdome’.