The Diocese of Aberdeen was originally believed to be the direct continuation of an 11th-century bishopric at Mortlach in present-day Moray. However, this early date and the first bishops were based on a misinterpretation and reliance on the early charters found in the cartulary of Aberdeen Cathedral. These charters are now known to be false. The first recorded bishop of the diocese was Nectan, mentioned in the Book of Deer around 1132. The earliest direct written evidence of a bishop in Aberdeen appears in a papal bull addressed to Bishop Edward in 1157. This bull acknowledged the existence of his cathedral, discussed the formation of a chapter, and marked the beginning of the diocesan expansion.

The parochial system in Scotland had been developing since the early Middle Ages and saw significant progress under David I. He clarified the rights of the local church in terms of territory and jurisdiction. His reforms ensured that parishioners could support their priests by providing tiends, while local lords retained their rights to build churches and appoint priests. Over time, the lords’ patronage shifted to cathedrals and monasteries, enriching these institutions at the expense of the parishes. The cathedral, with its expanding number of canonries, used the appropriated income to sustain itself. The beneficiary canons had a duty to ensure an income for the parish vicars although the stipends were generally meagre.

Reconstruction of the cathedral began in the late 14th century and extended into the 16th century.

History of the diocese

The diocese’s likely mythic origins are recorded in the cathedral’s chartulary, associating its early bishops—Bean, Denortius, Cormac, and Nectan—with Mortlach in present‑day Moray.Innes, Registrum Episcopates Aberdonensis, Vol. 2, pp. 246–7 This tradition rests on a series of early charters that are acknowledged to be false.Cowan & Easson, Religious Houses, p. 202Innes, Registrum Episcopates Aherdonensis, Vol. 1, pp. xii – xixWatt & Murray, Fasti, p. 1 These charters allowed Hector Boece to construct a history that had successive Mortlach bishops, culminating with its fourth prelate, Nectan, who would then move his see to Aberdeen. Beyond his appearance in one of these spurious charters, Nectan is only once documented as bishop of Aberdeen—in a small note (c. 1132) found in the Book of Deer.Oram, Medieval Church in Aberdeen and Moray, p. 17 Nevertheless, Mortlach did possess early ecclesiastical significance. A Papal Bull of 1157 by Pope Adrian IV confirmed the existence of a monasterium at Mortlach along with five attendant churches as part of the diocese of Aberdeen. By the 11th century, this type of organisation was characteristic of Culdee (Céli Dé) settlements—the Culdees resembled communities of secular priests ministering to local populations but directed from the central mother church (the monasterium).Cowan, Medieval Church in Aberdeen, pp. 21–22

Pope Adrian IV's bull of 1157 also confirmed to Bishop Edward the churches of Aberdeen, St Machar and St Nicholas, together with the town of Old Aberdeen and other lands.Dowden, Bishops of Scotland, p 99Innes, Registrum Vol 1, pp. 4–5 The bull authorised bishop Edward to establish a chapter in his cathedral, giving him the choice of introducing regular or secular canons as his clergy, but nothing immediately came of this.Watt, Fasti, p. 6 The lack of a means of funding a fully functioning unit of clerics may have accounted for this. Reforms in the 12th century were partially driven by local landowners who provided churches and priests, leading to a diminished importance of mother churches.Cowan, Medieval Church in Aberdeen, p. 22-3 The strongest stimulus for change happened under the influence of King David I. He introduced an ordinance that guaranteed the rights of the parochial churches and their priests who were to be sustained by the collection of teinds. Consequently, and particularly in areas of extensive feudal expansion by Anglo-Norman lords (such as in the diocese of Aberdeen), geographically based and viable parochial entities emerged within the diocese. These local lords—with some regard for the afterlife—granted their right of patronage over parish churches to the cathedral or a monastery of their choosing. This, combined with the establishment of new monasteries, considerably impacted the Culdee mother churches and pendicle churches. Some were reduced to ordinary parish churches, such as Mortlach and Cabrach, while others, more rarely, were transformed into organisations that more closely resembled their former existence. For instance, Monymusk became a house of Augustinian canons regular.Cowan, Medieval Church in Aberdeen, p. 23

The mechanism by which the diocese could generate income was now in place: parish churches, with their guaranteed income, would soon be subjected to appropriation by the monasteries and cathedrals. At Aberdeen, the annexation process may have begun as early as Bishop Edward's tenure and increased in line with the development of the chapter.Cowan, Medieval Church in Aberdeen, pp. 24–5 The enlargement was slow with incremental appointments of dignitaries continuing through to the mid-13th century when in 1249 Pope Innocent IV issued a bull to Bishop Peter Ramsay confirming the diocese constitution and a chapter consisting of five dignitaries and eight ordinary canonries all sustained on prebends.Oram, Medieval Church in Aberdeen and Moray, pp. 17–18

Appropriation of parish incomes to prebendary canons in the cathedral weakened the parish churches. The cathedral canons, possessed of the fruits of both the parsonages and the vicarages, were responsible for appointing vicars to the parishes. Invariably, vicars were paid meagre pensions and lacked security of tenure. This resulted in inadequately educated clerics being appointed to discharge the cure of souls.Cowan, Medieval Church in Aberdeen, p. 24

By 1488, the cathedral chapter had expanded to twenty-nine canons supported by the income from fifty-four parish churches; of those, forty-two were prebendal, one mensal and eleven held in common. Additionally, forty-two other parish churches were appropriated to monasteries and other ecclesiastical foundations, leaving only four parishes—Cushnie, Forvie, Tough, and Tyrie—as independent entities. The diocese also included eleven hospitals/almshouses for the poor, aged, or infirm parishioners. The religious Orders were also well represented: a Tironensian priory at Fyvie, a priory of Augustinian canons at Monymusk, and a Cistercian monastery at Deer. Similarly, the Carmelite, Dominican, Franciscan, and Trinitarian Friars all had houses in Aberdeen itself. Macfarlane, Elphinstone, pp. 204–5

The reconstruction of the cathedral began when Bishop Alexander Kininmund (1355–80), probably nearing the end of his episcopacy, heightened the walls of the west towers and the nave. Bishop Henry Lichton (1422–40) completed what Kininmund had started and established the north transept, but left the construction of the central tower incomplete. He was followed by Ingram Lindsay (1441–58), who roofed and paved the nave. Thomas Spens (1457–80) finely furnished the interior, and Bishop William Elphinstone completed the central tower begun by Lichton. Elphinstone also commenced the rebuilding of a larger choir. Gavin Dunbar (1518–32) completed the south transept and provided spires for the west towers. Dunbar was also responsible for the armorial-adorned ceiling in the nave, displaying the coat of arms of the pontiff, Scottish prelates, and leading European rulers.Fawcett, Scottish Cathedrals, pp. 64–5

Religious houses The bishop held authority over the cathedral, parish churches, and hospitals. While the monasteries were largely independent of the episcopacy they still required the bishop if any of the brothers needed to be ordained to the priesthood. The monastic houses may occasionally receive patronage from the bishop and chapter.

The cathedral Bishops

Nectan, fl. 1131/2 Edward, fl 1147/51-1171 Matthew, 1172–1199 John, 1199–1207 Adam de Kalder, 1207–1228 Matthew Scot, postulated 1228 Gilbert de Stirling, 1228–39 Radulf de Lambley, 1239–47 Peter de Ramsey, 1247–56 Richard de Potton, 1256–70 or 1272 Hugh de Benin, 1272–82 Henry le Chen, 1282–1328 Walter Herok, elect and provided but not consecrated, 1329 Alexander de Kyninmund (I), 1329–1344 William de Deyn, 1344–1350 John Rait, 1350-1354/5 Alexander de Kyninmund (II), 1355–80 Simon de Ketenis, elected 1380 but not provided Adam de Tynyngham, 1380-9 Gilbert de Greenlaw, 1390–1421 Henry de Lychton, 1422–1440 translated from Moray Ingram Lindsay, 1441–58 Thomas Spens, 1457–80 translated from Galloway Robert Blackadder, 1480–83 William Elphinstone, 1483–1514 translated from Ross Alexander Gordon, 1514/15-18 Robert Forman, before 1515–16 Gavin Dunbar, 1518–32 George Learmond, 1529–31 William Stewart, 1532–45 William Gordon, 1545–77

Cathedral chapter The development of Aberdeen's chapter was lengthy, even though the papal bull of 1157 authorised Bishop Edward to institute a chapter of secular or monastic clerics. The first signs of chapter enlargement became apparent when a cleric designated as a 'canon' witnessed an act by Bishop John (1199–1207). His successor, Bishop Kalder (1207–1228), had many canons serving on synodal sittings who confirmed his episcopal edicts, with an archdeacon as the senior cleric. Bishop Stirling (1228–1239) continued this system, but the assembly was now called a 'chapter' and possessed its own seal. A canon was now designated 'treasurer' with the dean still subordinate to the archdeacon. By 1239, Bishop Lamley had been elected at a meeting chaired by the dean, although apparently, the archdeacon was still his senior. In c. 1239, a canon had been elevated to the dignity of precentor, and then in 1240, a chancellor was visible. In 1243, a meeting of the chapter demonstrated a change in its structure; the dean was now the senior canon.Watt & Murray, Fasti, pp. 6–7 By 1445, the chapter consisted of twenty-nine canons; the dean, presenter, chancellor, and treasurer were the dignitaries (the archdeacon was no longer a dignitary), and 24 simple canonries made up the remainder.Cowan, Medieval Church, pp. 62–3 The last canonry to be created was that of the sub-chanter (1527x1534), bringing the total number of canons to 30. Between them, the chapter held 46 appropriated churches in the diocese of Aberdeen and a further 2 in the diocese of Moray.Cowan, Medieval Church, pp. 33–4