In the summer of 1455 Duke Borso d’Este received a letter from the Bishop of Ferrara, Francesco dal Legname, warning him that Ferrara might lose one of its most illustrious nuns. The bishop had heard from the abbess of the Poor Clares convent of Corpus Christi that their mistress of novices, Sister Caterina Vigri, had been selected as abbess of a new house in Bologna. Borso replied through his secretary, Ludovico Casella, reassuring him that something would be worked out so that Ferrara would not lose ‘that holy woman’. The woman in question had been Borso's childhood commpanion at the d’Este court and a lifelong friend of his sister Margherita d’Este. Neither the bishop nor the duke could prevent Vigri's departure for Bologna with a dozen sisters on 22 July, 1456. Corpus Christi continued to flourish, but only later did Ferrara replace this holy woman who had benefited Ferrara's reputation and helped maintain the wellness of the civic body. The incident is an extraordinary testament to the civic status of an enclosed nun.

Now known as Corpus Domini but called ‘Corpus Christi’ in the fifteenth century (the name that will be used in this text), this convent was for 30 years home to the mystic, writer, teacher and nun-artist Caterina Vigri (1413‒63), who later became Saint Catherine of Bologna. This volume focuses on the formative period of her life, her writings and her artwork in the convent culture of the Poor Clares in Ferrara. The Observant Franciscan spirit is epitomized in her charismatic teaching as ‘Mistress of Novices’. Her large body of writings based on scriptural, Patristic and Franciscan sources suggest that she and her audience were mostly literate, well-educated women. Using her own ‘little book’, she taught poverty, humility, active prayer and obedience. Her reputation for holiness, fasting and prayer fueled the convent's dynamic growth and patronage, and helped establish its pious reputation. Vigri's Sette Armi Spirituali has been studied as a private spiritual treatise reflecting mystical visions of Christ, but it is also a practical didactic text for aspiring nuns. Sister Caterina vividly recounts her visions of Christ, and the machinations of the devil, who appears in the guise of the Virgin or even Christ himself.