Alvarez, Diego, Spanish theologian, b. at Medina de Rio-Seco, Old Castile, about 1550; d. at Trani, Kingdom of Naples, 1635. He entered the Dominican Order in his native city, and taught theology for twenty years in the Spanish cities of Burgos, Trianos, Plasencia, and Valladolid, and for ten years (1596–1606) at the Minerva, in Rome. Shortly after his arrival in Rome (7 November, 1596) he presented to Clement VIII a memorial requesting him to examine the work "Concordia liberi Arbitrii", by Ludovicus Molina, S.J., which, upon it publication in 1588, had given rise to bitter controversy. Before the Congregation (Congregatio de Auxiliis), appointed by the Pope to settle the dispute, he defended the Thomistic doctrines of grace, predestination, etc., alone for three years, and, thereafter, conjointly with Thomas de Lemos, O.P., to whom he gave the first place, until the suspension of the Congregation (1606). He was appointed, 19 March, 1606, by Paul V, to the Archbishopric of Trani, where he passed the remainder of his life. Besides (1) a commentary on Isaias, and (2) a manual for preachers, he published: (3) "De auxiliis divinæ gratiæ et humani arbitrii viribus et libertate, ac legitimâ ejus cum efficaciâ eorumdem auxiliorum concordiâ libri XII" (Rome, 1610; Lyons, 1620; Douai, 1635); (4) "Responsionum ad objectiones adversus concordiam liberi arbitrii cum divinâ, præscientiâ, providentiâ, et prædestinatione, atque cum efficaciâ prævenientis gratiæ, prout a S. Thomâ et Thomistis defenditur et explicatur, Libri IV (Trani, 1622; Lyons, 1622); (5) "De origine Pelagianæ hæresis et ejus progressu et damnatione per plures summos pontifices et concilia factâ Historia ex annalibus Card. Baronii et aliis probatis auctoribus collecta" (Trani, 1629); (6) "Responsionum liber ultimus hoc titulo: Opus præclarum nunquam hâctenus editum, in quo argumentis validissimis concordia liberi arbitrii cum divinâ præscientiâ, prædestinatione, et efficaciâ gratiæ prævenientis ad mentem S. Thomæ et omnium defenditur et explicatur" (Douai, 1635); (7) "Operis de auxiliis divinæ gratiæ et humani arbitrii viribus et libertate, ac legitimâ ejus cum efficaciæ eorumdem auxiliorum concordiâ summa, in IV libros distincta" (Lyons, 1620; Cologne, 1621; Trani, 1625); (8) "De incarnatione divini verbi disputationes LXXX; in quibus explicantur et defenduntur, quæ in tertiâ parte summæ theologicæ docet S. Thomas a Q. 1 ad 24" (Lyons, 1614; Rome, 1615; Cologne, 1622); (9) "Disputationes theologicæ in primam secundæ S. Thomæ, in quibus præcipua omina quæ adversus doctrinam ejusdem et communem Thomistarum a diversis auctoribus impugnantur, juxta legitimum sensum præceptoris angelici explicantur et defenduntur" (Trani, 1617; Cologne, 1621).
Echard, Scriptores Ordinis Prædicatorum (Paris, 1721), II, 481; Ughelli, Italia Sacra (Venice, 1720), VII, 1240; Hurter, Nomenclator (Innsbruck, 1892), I, 263; H. Serry, Historia Congregationum de Auxiliis (Antwerp, 1709).