The invitation to Roseman and his colleague Ronald Davis from the nuns at the Certosa di Riva was due to a thoughtful letter of recommendation from the Prior Emeritus Nicholas Barras of the Chartreuse de la Valsainte, the Carthusian monastery in the Swiss Alps where the artist drew the hermit monks. (See the page "Benedictines, Cistercians, Trappists, and Carthusians," Page 4 - "Carthusians.") The solitude of Carthusian monasticism accounts for the relatively small number of monasteries, today numbering twenty-three, compared to the much larger number in the Benedictine, Cistercian, and Trappist Orders. In 1982, the Certosa di Riva was one of only six convents in the Carthusian Order, which dates from 1084.