GIOVANNI di VESALIA (JOHANN von WESEL). — Theologian, whose real name was Johann Rucherath or Richerath, born at Oberwesel at the beginning of the 15th century, died at Mainz in 1481. Nothing is known of his early youth; reliable information about him begins only in 1440, the year in which he entered the University of Erfurt. There, in 1445, he obtained the degree of magister artium, and subsequently received his doctorate in theology on 15 November 1456. He also taught there for several years, until he went to Worms in 1460 as a canon. He was also professor of theology at Basel, but soon returned to Worms (1463) as preacher at the Cathedral, an office he retained until 1477, when he was deposed by the bishop Reinhard von Sickingen because of the scandal aroused by his sermons, which were directed especially against the Church of Rome.
Shortly thereafter, however, he obtained a similar position in the cathedral of Mainz, where he had been summoned by the archbishop Diether von Isemburg. There he established relations with a Bohemian Hussite, a certain Nicolaus, for whom he wrote the treatise Super modo obligationis legum humanarum ad quendam Nicolaum de Bohemia, intended for the Hussites. Consequently summoned before a tribunal of theologians from the Universities of Cologne and Heidelberg, he retracted his errors (21 February 1479), but was nevertheless confined for life in the Augustinian monastery at Mainz. The errors of G. di V. Church, which he regarded as an invisible society (quam nemo sciat nisi Deus), indulgences, predestination, the veneration of the saints, and transubstantiation correspond approximately CHUS (v.).
The writings of G. di V., some of them still unpublished, are: Adversus indulgentias disputatio (ed. Ch. W. F. Walch, in Monumenta medii aevi, II, 1, Göttingen 1757, pp. 111–156), directed against the papal indulgence for the jubilee year 1450; Opusculum de auctoritate, officio et potestate postorum ecclesiasticorum (ed. Walch, op. cit., II, II, p. 142 ff.), in which he denounced the faults of both the higher and lower clergy; De potestate ecclesiastica; De indulgentiis and De ieiunio, now lost. Finally, the two treatises De processione Spiritus Sancti and De peccato mortali are of doubtful authorship.