INSTITORIS, HEINRICH (Henricus de Sletstal). — Dominican theologian, born in Schlettstadt ca. 1430, died in Moravia in 1505. He was teaching theology when Bishop Rudolf of Lavant commissioned him to preach a crusade against King George Poděbrady of Bohemia. On March 13, 1479, Sixtus IV appointed him inquisitor over all Upper Germany, where he began the struggle against heretics, particularly witches, especially in Constance, Bressanone, and Innsbruck. Alexander VI (January 31, 1500) named him nuncio and inquisitor in Bohemia and Moravia against the “Moravian Brethren.”
He left many writings against heresy and in defense of the papacy; noteworthy are: *Malleus maleficarum* (Lyon 1484), written in collaboration with Jacob Sprenger; *Tractatus varii contra 4 errores novissime exortos adversus Eucharistiae sacramentum* (Nuremberg 1496); *Tractatus adversus errores A. Roselli de plenaria potestate pontificis ac monarchiae* (Venice 1499); *Opus perutile sermonum in defensionem S. Romanae Ecclesiae adversus Waldenses* (Olmütz 1501); *S. Romanae Ecclesiae fidei defensionis Clypeus adversus Waldensium seu Pickardorum haeresim* (ibid. 1502).