These numbers are much reduced in 1381, with only 28 nuns, besides the prioress. At the time of the Dissolution of the monasteries and the Priory's closure in 1539 there seem only to have been the prioress and 33 nuns. As the 14th century closed, Dame Sybil became embroiled in some notable events. Firstly, in May 1398, some 7 years after her election as prioress, an inquiry was ordered by the King into the government of the priory with a view to reforming it according to the ordinances and constitutions. Among other indications of indiscipline was the birth of a child in 1398 to a nun of Amesbury, Margaret Greenfield, but in general motives and outcome are unknown. It is known, however, that before January 1399 Dame Sybil showed a decisive temperament by having the elderly Prior Robert Daubeneye thrown out of the monastery. In the uproar of accusations and counter-accusations that followed, Dame Sybil emerges as high-handed and the mixed royal and ecclesiastical enquiries were favorable to the Prior and his reputation as a priest in good standing, though he was not reinstated but was ordered to receive a pension. However, on 14 March 1400 there was an astounding sequel when ruffians invaded the monastery after nightfall and Sybil some of the nuns were imprisoned for at least two days, the prioress was manhandled and perhaps the monastery's treasure was carried off. Upon her prompt complaint, Henry IV, crowned king on 13 October 1399, issued orders to officers of the crown to free the nuns and restore order, since “evildoers of the town have taken and imprisoned” them. The official investigations brought to light an attempt of Dame Sybil to pare down the number of canons from twelve to four, replacing them with secular priests. This was a delicate moment since in 1388 Richard II, to whom Sybil's male relatives were steadfastly loyal, had been deposed by Henry IV. Her brother John had been heavily caught up in resistance to the new king and was imprisoned by a mob at Cirencester and without trial beheaded on 7 January 1400, three months before the irruption at Amesbury. Those days were but a memory when Sybil's next storm arose, related perhaps to the long political and military struggles between the crowns of England and France. These meant a variety of problems for the so-called alien priories, that is, those monastic houses, usually small, that were dependencies of foreign, usually French, mother houses.