HEINBUCHE von LANGENSTEIN, HEINRICH (HEINRICH von HESSEN). - German scholar and theologian of the 14th century, also known as Heinrich of Heinbuche or the elder Heinrich of Hesse. In 1363, he became a Master of Arts in Paris; he lectured on astronomy and natural sciences (Quaestio de cometa, 1368; Contra astrologos, 1371). Later, he earned a doctorate in theology and Sacred Scripture, and in 1378 he became vice-chancellor of the University. However, in 1382 he left Paris to follow Urban VI to Eberbach and Worms. Invited by Albert III, in 1383 he went to Vienna to organize the University (founded in 1363), of which he served as rector (1393–94) and renowned professor until his death (11 February 1397).
Of vast erudition, besides many theological writings—among them one in favor of the Immaculate Conception, the *Contra maculam beati Bernardi*—he owes his fame to his work during the Western Schism as a supporter of Urban VI and, in particular, as an advocate of the conciliar theory, which he was the first, together with Conrad Gelnhauser, to formulate. On this subject, he wrote the dialogue *Epistola pacis* (1379), the *Epistola concilii pacis* (1381), the *Invectiva contra monstrum Babylonis* (1393), *Super cathedram Petri* (1395), *De futuris Ecclesiae periculis*, and others. He held that the ecumenical council, as the integral representation of the Church, had the right to examine the legitimacy of a doubtful papal election.