Dublin’s cathedral was dedicated to the Holy Trinity, but the name "Cristchirche" emerged in 1444. The cathedral was probably founded around 1028, the year the Hiberno-Norse king, Sitriuc "Silkenbeard," made a pilgrimage to Rome. Due to canon law irregularities in the organization of the Irish Church, Dublin was to become a suffragan diocese of Canterbury from at least 1074, following the consecration of its second bishop, Gilla Patraic. With Muirchertach Ua Briain as secular ruler of Dublin, together they laid the foundations of what would become the twelfth-century church reform.
Gilla Patraic introduced the first of the religious orders to Holy Trinity: Benedictine monks, who remained until their expulsion around 1100 by Bishop Samuel. It was during his episcopate that the Dublin diocese was subsumed into Glendalough under the 1111 synod of Raith Bressail, and not until the synod of Kells in 1152, under Bishop Grene, did Dublin diocese and Holy Trinity cathedral achieve archiepis-copal and metropolitan status, respectively. Lorcan Ua Tuathail, brother-in-law of Diarmait Mac Murchada, succeeded in 1162 and established a priory of Augus-tinian canons regular at the cathedral.
Following the Anglo-Norman invasion of Dublin in 1170, property granted to the cathedral priory by former Irish and Hiberno-Norse kings was confirmed by Henry II and his son John. This was an estimated 10,500 acres arranged under the manorial system, including Grangegorman, Clonkeen, Glasnevin, and Balscadden. Both Lorcan (d. 1180) and Richard de Clare "Strongbow" (d. 1176) predeceased the Romanesque rebuilding of the cathedral traditionally attributed to them. Building work by English West Country masons began in the mid-1180s under the first Anglo-Norman archbishop, John Cumin. In 1216, under his successor Henry of London, Holy Trinity became the diocesan cathedral for Glendalough following its unification with Dublin. By 1220, St. Patrick’s cathedral had been founded by Henry, and the remainder of the century saw an architectural and constitutional jostling for supremacy between Holy Trinity’s regular and St. Patrick’s secular chapter. A Gothic nave (1230s), partially extant, and an extension to the chancel (1280s) were built at Holy Trinity. However, the constitutional wrangling ceased only when, in 1300, both signed a composicio pacis acknowledging both as diocesan cathedrals, but Holy Trinity as the elder. Surviving fire in 1283 and the fall of the steeple in 1316, Holy Trinity was an accustomed venue for the Irish parliament, which often met, as in 1450, in the common hall. The belfry was rebuilt by 1330, and by 1337 to 1342, the surviving account roll gives a glimpse of the priory’s administration, the records of which are unusually plentiful for an Irish medieval institution. Despite recurrent outbreaks of plague from 1348, the next decades saw a choir extension built by Archbishop John de St. Paul and the acquisition of an English illuminated psalter by Prior Stephen de Derby. In 1366, the Kilkenny statutes disqualified the native Irish from membership of the chapter.
Richard II knighted four Irish kings in the cathedral in 1395, while the coronation of the Yorkist pretender Lambert Simnel as King Edward VI took place at Christ Church in 1497. St. Augustine’s rule defined the priory’s religious life, enhanced by liturgical manuscripts such as the martyrology, psalter, and a book of obits. These were used in chantry chapels such as St. Lo (1332) and St. Laurence O’Toole (1485) and were enhanced by a choir of four choristers in 1480, whose education by a music master was confirmed by Prior David Wynchester in 1493. The most elaborate chapel was a perpendicular gothic chantry dedicated to St. Mary, built in 1512 by Gerald Fitzgerald, eighth earl of Kildare, who was buried there the next year.
Holy Trinity also led the moral and religious instruction of Dubliners. In 1477, the archbishop of Armagh and papal nuncio, Octavian de Palatio, preached there in support of a crusade against the Turks. The earliest known morality play from Ireland, The Pride of Life, survived in the fourteenth-century priory account roll, and in 1528 the priors of Holy Trinity, Kilmainham, and All Hallows attended performances of passions at Hoggen Green.
Commerce coexisted with this world, with many guilds or fraternities having chapels at Holy Trinity, such as the merchants’ Trinity guild (1451) or the guild of St. Edmund, asked in 1466 to provide bows and arrows for the defense of the city. Shops soon emerged from crypt cellars. The "utestale[s]" mentioned in 1423 had oaken beams and stone roofs by 1466. Internally, maintenance was continuous. Four windows were newly glazed in 1430 in St. Mary’s chapel, a structure with a complex building history, little of which survives. South of it lay the long quire where, in 1461, the east window blew in, destroying numerous relics but notably excluding the Baculus Ihesu (staff of Jesus). The priory’s earnest protection of visiting pilgrims’ "immunities," as in 1493, can be attributed to the lucrative supply of income that they provided. The cathedral’s relics were publicly burned in 1538 by Archbishop George Brown. Christ Church was the sole religious house to survive the dissolution of the monasteries in 1539, abandoning its monasticism for a secular constitution based on St. Patrick’s. Henry VIII confirmed Prior Castle, alias Payn-swick, as first dean in 1541, and by 1544, three prebendal parishes were established: St. Michael’s, St. Michan’s, and St. John’s. If not the Reformation, then certainly the fall of the roof and south wall of the nave in 1562, partially destroying the Strongbow monument, signalled the end of the medieval period.
