ALGERO of LIEGI. – Theologian and canonist (1602–1131). Born in a region particularly attached to the emperor and therefore strongly oscillating between imperial and papal politics, he lived through the entire Investiture Controversy. A scholastic of Saint-Bartholomew’s in Liège, in 1101 he was promoted canon of Saint-Lambert by Bishop Otterbo, loyal to Emperor Henry IV, who only submitted to the Pope in 1106, ending the schism. At that point, both the people and the clergy rallied to the Gregorian party: it was precisely at this moment that A. wrote *De misericordia et iustitia* to defend the canonical provisions of Gregory VII and to delineate the relationship between Pope and Emperor. His fame spread to Germany, and German bishops sought his services, but, a man without ambition, he preferred to remain in his homeland. Upon Otterbo’s death (1119), a new division arose over the election of his successor; A., now weary of so many struggles, retired to Cluny, which at that moment enjoyed peace and prosperity under the wise governance of Peter the Venerable. There he received priestly ordination and prepared for death, earning a flattering encomium from his saintly abbot. His biographer and colleague in the chapter, Nicholas of Liège, thus portrays A.’s character: «Erat subtilis ingenio, facundus eloquio, in proposito stabilis et quod his omnibus est pretiosius existimabatur et erat tam fide quam doctrina catholicus» (Elogium Alg., Leod.: PL 180, 737).
Passing over the lost letters and *De dignitate Ecclesiae Cathedralis*, as well as the *De libero arbitrio* and the *Liber Sententiarum Magistri A.* of doubtful authenticity, we must focus on the two works that link A.’s name to theology and canon law. As noted above, the occasion for writing *De misericordia et iustitia* was the defense of canonical provisions after the resolution of the schism; it was first published by Dom Martène in 1717 and reprinted in PL 180, 857–908. The author begins by highlighting the strong antinomy of canon law: some canons are very severe, others too lenient, so much so that in their application they leave the mind oscillating between condemnation and forgiveness. This contradiction, A. explains, arises from ignorance of the circumstances under which the canon laws were promulgated: the Church sometimes pardons, while at other times punishes, taking into account the particular contingencies in which the crime was committed. It is not the letter but the spirit of the law that must be grasped from the texts, so as to harmonize them: «Ad haec elaboratio, ut in canonibus adeo intentionis, utilitatis, veritatis eluceret unitas, ut nullam contrarietatis discordiam pararet aliqua eorum diversitas» (col. 858). The work is divided into three parts (comprising 358 chapters): the first treats of mercy, i.e., of indulgence, noting the cases in which it should be applied; the second discusses justice, i.e., the manner of applying *strictum ius*; the third tackles the burning issue of heresies and the validity of sacraments administered by heretics. More practical than speculative, the book addresses the special difficulties A. faced after his submission to the Pope: many delicate cases concerning excommunicated, simoniacal, and married priests needed resolution. The work is of particular interest today as one of the earliest essays on the theory of legal interpretation. To resolve interpretive divergences, A. followed a method derived from Abelard’s *Sic et Non*, which was later adopted by Gratian; it is also important as a collection of canonical legal sources, for A. gathered in it—drawing on various earlier collections—many texts from the Fathers, 125 decretals, and fragments of letters by Saint Gregory the Great (in Gratian’s *Decretum*, about a hundred texts and sixteen dicta are drawn from A.’s work).
As a theologian, A. is always remembered for his *De sacramentis corporis et sanguinis dominici*, preserved in many manuscripts and first printed by Erasmus in 1530 at Freiburg im Breisgau alongside Guittmond of Aversa’s analogous work, in order to oppose Protestant innovations with the doctrine of four centuries earlier. Many other editions followed, including that of the Roman Ulmer (1561), reprinted by Malou (1847), Migne (PL 180, 737–856), and P. Hurter (SS. Patrum opuscula selecta, XXIII, Innsbruck 1873, pp. 58–370). Composed between 1110 and 1121, the work is divided into three books: the first and most important, in 22 chapters, treats *de veritate et virtute corporis Christi*. After an introduction on the importance of the Eucharist in the divine economy (chs. 1–3), the two aspects of truth and figure in the Eucharistic mystery are examined; the dominant idea is clear, though its development is not always so. Three concepts, however, recur with sufficient clarity: the body of Christ is present in the sacrament (chs. 4–8), the same body born of Mary (chs. 9–16), and the sacramental presence does not impair the reality of the body born of the Virgin (chs. 17–22). The second book (10 chapters) consists of a series of *quaestiones* that yield valuable complementary clarifications. The third (14 chapters) addresses the validity of sacraments “extra Ecclesiam” and defends their validity with rigorous argumentation. In this work, besides a vigorous affirmation of real presence—shown not to be impaired by the figurative nature of the sacrament—doctrines of transubstantiation and the permanence of the accidents are sketched as a prelude to the syntheses of the 13th century. On the question of sacrifice, A. follows the Augustinian line with this felicitous formula: «Christus in sacramento quotidie non passus sed quasi pati repraesentatus» (PL 180, 787). Even more felicitous are the words expressing the participation of the faithful in the sacrifice of the Mass: «In altari Ecclesia concorporalis et consacramentalis est Christo» (ibid., 847).
The scholastic of Liège fittingly closes the ranks of the great opponents of Berengar of Tours (d. 1088) and merits the praise of Peter the Venerable: if Lanfranc wrote *bene plene et perfecte* on the Eucharist, if Guittmond *melius plenius et perfectius*, Algero [wrote] *optime plenissime et perfectissime* (Contra Petrobrusianos: PL 189, 788).