The Poissy nuns performed long and complicated services that varied by day and hour. They were always expected to sing the daily Canonical Hours, which are eight services — called lauds, prime, terce, sext, none, vespers, compline, and the night office — that are performed at regular intervals through the day. Each service ended with a prayer called The Little Office of the Virgin Mary, which changed according to the days of the week. In addition, the nuns were obliged to participate in High Mass, and they observed and engaged in the services for feast days and for major personal or courtly events at the convent, like official visits, religious professions, and death and mourning services.
The nuns’ schedule demanded that they enter the choir in the early hours of the morning, and spend many hours singing each day. In fact, Phillipe le Bel’s founding letter to the Provincial of France specified that the Poissy nuns should be able, “to read and to sing in unison… [be] robust enough to carry the burden of a religious life and keep the accustomed observances and … to instruct and efficiently train new arrivals to the convent in the customs, skills and duties of religious life.” Beyond that, they were supposed to memorize the office of the dead as well as the psalms of the daily, hourly, and weekly vespers.
The Bryn Mawr College manuscript is a type of prayer book called a processional. It mostly contains prayers and chant notation for special processions performed on feast days. These prayers were performed as excursions to various parts of the church and convent, during which the nuns left their choir stalls in the center of the nave, and, led by clergy who carried ritual objects like candles or a processional cross, walked, chanting, through the church and cloisters, stopping to say prayers at set locations in the church.
Joan Naughton describes how the processional office for Palm Sunday (ff. 7v-21 in our manuscript) would have been enacted at Poissy. The feast, which commemorates Christ’s triumphal entry into Jerusalem, would have taken place after terce, which is the third canonical hour and is performed around 9 am, depending on the time of year. Naughton writes that after the prior, deacon, subdeacon, and acolytes entered the church to bless the palms (ff. 7v-9), nuns sang the antiphons (ff. 10-10v) and distributed palms in the choir. After a reading from the Gospel (ff. 11-11v), they presented a processional cross and holy water to two sisters. These sisters, or “nun-bearers,” led the procession from the nave to the cloisters, where they made three stations (ff. 11v-19v). They then re-entered the church, singing the responsory that begins “Ingrediente domino in sanctam civitatem…,” which means “With the lord entering into the holy city…,” metaphorically re-enacting Christ’s entry into Jerusalem (ff. 19v-21v). Finally, they put aside the palms, and the prior began mass.
The Poissy processionals were made for individual use and were individualized in their content. As the intimate scale of our book suggests, each nun would have walked with her own processional. Although prayerbooks were often passed through and across generations of nuns, an owner’s name might still be inscribed in a manuscript, as was permitted by medieval Dominican custom. None of the processionals share exactly the same collection of prayers, although some services are common to most and there is generally a significant overlap among manuscripts in verbal and musical texts. The manuscripts also vary somewhat in the ordering of the processions and in the chants that they include for particular services.
In addition to processions that mark regular points in the holy calendar, the manuscripts sometimes included services performed for welcoming royalty and high-ranking church officials, for the reception of novices, and for the profession of nuns. Processionals could also contain services concerned with death and dying, which often appear in other sorts of volumes, for instance, in books of hours. Very few books of hours can be attributed to the Poissy convent. The Bryn Mawr manuscript, which has been altered and rebound since its creation, now ends abruptly in the middle of the services for the Maundy Thursday washing of altars, and it is therefore impossible to know whether it might once have included funerary services.
Despite variations in the contents and ordering of individual manuscripts, Dominican service books were supposed to be regulated so that they would include only approved texts. An official of the Dominican order visited each house regularly and checked its books against a standard version.
Several markers tie our book particularly to the royal convent at Poissy. The most explicit of these is a rubrication, or additional, instructional text in red ink, on folio 114, which reads, “Ordo altarium abluendorum in cena dominum in ecclesiam beati ludovici de pissiaco ad maius altare de beato ludovice ipsius ecclesie.” This is a direct reference to the church dedicated to Saint Louis at Poissy and to the high altar in that church that was also dedicated to Saint Louis. The rubrication is followed by a list that includes fourteen of Poissy’s twenty-one altars. The manuscript also contains a procession for Saint Louis (ff. 103v-107v), which appears in every Poissy processional after about 1320, as well as observances for John the Baptist (ff. 96v-100v) and for the Nativity of the Virgin, which seem to have been added to the Poissy services in the 1400s. Since Poissy was the only Dominican house to include these three services in its processionals, they are a strong indicator of the book’s origin. Dominican nuns followed the same liturgy as Dominican friars, but the use of feminine endings in some of our manuscript’s Latin prayers places the book with the Poissy nuns, rather than with their associated friars.
 Joan Naughton, Manuscripts from the Dominican Monastery of Saint-Louis de Poissy, Dissertation, The University of Melbourne. Melbourne: Minerva Access, 1995, 6.
 “…et cum oporteat, maxime in principio, tales eligere personas quae sciant legere et cantare, et quae talem habeant corporis valitudinem quod possint onera religionis portare ac servare observantias consuetas, et quae in posterum recipiendas in moribus et scientia et debito religionis verbo et exemplo efficacieter doceant et informent…” Bernard Gui, “E notitia provinciarum et domorum Ordinus Praedicatorum” in Bernard Gui, Recueil des historiens des Gaules et de la France, vol. 23. Paris, 1876, 190-1, as cited in Naughton, Manuscripts from the Dominican Monastery of Saint-Louis de Poissy, 43, n. 31.
 “…instruendi sunt in canto, et in legend, qui nesciunt, et addiscere possunt. In hoc repetendum est ab eis quidquid habent legere vel cantare in convent; et auscultandum et recitandum cordetenus illud quod de psalterio et divino officio cordetenus scire oportet; videlicet officium mortuorum, et de beata Virgine, psalmi de horis diurnis, et vesperarum per ferias.” Humbert of Romans, Opera de Vita Regulari, II, ed. J. J. Berthier (Turin, 1956), 299, as cited in Naughton, Manuscripts from the Dominican Monastery of Saint-Louis de Poissy, 61, n. 106.
 Anne Bagnall Yardley describes the performative aspects of processions in medieval convents. In particular, she notes that they offered a rare experience, since women were usually not prominent in processions outside convents. Occurring outside the nave or even outside the church, these processions allowed nuns to enter a liminal space outside the strict bounds of enclosure. See Anne Bagnall Yardley, Performing Piety: Musical Culture and Medieval English Nunneries (New York: Palgrave Macmillan, 2006), 113-158. For a broader discussion of medieval processions as performance, see Kathleen M. Ashley and Wim N. M. Hüsken, Moving Subjects: Processional Performance in the Middle Ages and the Renaissance (Atlanta, GA: Editions Rodopi, 2001).
 Naughton, Manuscripts from the Dominican Monastery of Saint-Louis de Poissy, 111.
 Naughton, Manuscripts from the Dominican Monastery of Saint-Louis de Poissy, 183-4.
 Naughton lists the services that are included in twenty-three processionals that she associates with Poissy. Naughton, Manuscripts from the Dominican Monastery of Saint-Louis de Poissy, Appendix 5c.
 When Master General, Humbert of Romans, standardized the Dominican liturgy in the 1250s he wrote that each religious house should have an antiphonary with plainchant and rubrics for its cantor and processionals (ending with burial services) for the rest of the congregation. William R. Bonniwell, A History of the Dominican Liturgy (New York City: J.F. Wagner, 1944), 89-90.
 Michel Huglo, Les Livres de Chant Liturgique (Brepols: Belgium, 1988), 91.
 These are listed in Suzanne Moreau-Rendu, Le Prieuré royal de Saint-Louis de Poissy (Colmar, 1968).
 Naughton, Manuscripts from the Dominican Monastery of Saint-Louis de Poissy, Appendices 5-6.