The actual date of the house's foundation is not clear. King Stephen, by charter, gave his lands in the fields of Norwich, and a meadow adjoining the land charged to God and the Church of St. Mary and St. John, of Norwich, and the nuns serving there. Stephen directed that such nuns should found their church on such land. They were to hold such lands as freely as the king himself did. Upon this, two of the nuns, who were sisters, Seyna and Lescelina, are said to have begun building the priory in 1146, eight years before Stephen's death, and to have dedicated it to "St. Mary of Carhowe," from which it would seem this was an offshoot of a Norwich nunnery dedicated to St. Mary and St. John (now unknown). The Benedictine nunnery, usually called Carrow Abbey, though only a priory, was founded for a prioress and nine "black nuns", but afterwards twelve nuns were part of its foundation.
In the second year of Stephen's reign the nuns endeavoured to obtain an enlargement of the house's grounds and gave the king a sparrowhawk for having the words cum omnibus libertatibus et liberis consuetudiuibus ad liberas ferias pertinentibus substituted in their charter for the words ad hujusmodi ferias pertinent, and in the next year the corresponding entry occurs on the Pipe rolls. It was not, however, till June of King John's 7th year of reign that the nuns obtained their amended charter. King Henry III, in the 13th year of his reign, confirmed the gift of the land, but is silent as to the cost; in his 19th year, he gave them a general confirmation; and in the 56th year, he confirmed the cost.
The early Rectors of Carrow Mediety, presented by the Prioresses of Carrow, were Robert de Cokethorp (1306), Richard Sekkesteyn of Herdwyk (1330), Richard de'Qirytewafh (1331), Robert King of Cnapeton (1335), John Akewra (1349), Thomas Cowles (1371), John Bale (1385), William Giffard (1388), Walter Aldous of Wingjield (1395), Nicholas Walter (1401), Thomas Catefby (1402), John Felys (1405). The anchoress Julian of Norwich was said to have received her training at the priory in the 1350/60s, and her writings indeed show Benedictine aspects.
In 1416 a dispute arose over ownership between the Prioress of Carrow and the Prior of Holy Trinity. The involved parties were Robert de Burnham, Prior of Holy Trinity (1407–1427) of County Norwich and Editha (Edith de Wilton) Prioress of Carrowe. The Prior pleaded that Editha was wrongly described as Prioress of Carrowe as Richard I. granted the City of Norwich to the citizens, and the city was in the County of Norfolk till Henry IV. separated it and made it a County of itself, which granted the citizens jurisdiction over Carrowe as "within a parcel of the City of Norwich."' The Prior further stated that Carrowe was in the parish of Bracondale which is in the County of Norfolk and was never in the City of Norwich. The court ruled in favor of the Prioress stating that Carrow was a parcel of the City of Norwich. Wills from the 15th century document many alternate spellings, such as Carhoe, or Carhowe; or Carehowe; or Carrowe.
Between 1529 and 1539 there were eight, two priests, and eight women-servants. The value of the lead, bells, and buildings was estimated at £145. In 1538 it was granted to Sir John Shelton, who lived there briefly until his death the following year.