Swiss humanist and scholar, the author of a chronicle of Swiss history that was used as a source by many subsequent writers, including Friedrich Schiller.

Though a pupil of the religious reformer Huldrych Zwingli (Zwingli, Huldrych), Tschudi remained a convinced and militant Roman Catholic; and his efforts to eliminate the Zwinglians came to be known as the Tschudikrieg (“Tschudi's War”; 1558–64). After holding several administrative posts, he became chief magistrate of Glarus.

Tschudi's enduring importance rests especially on the Chronicon Helveticum, 2 vol. (1734–36), a “Swiss Chronicle” covering the years 1000–1470. Many assiduously collected documents were incorporated in it; others were fabricated, in an attempt to give a coherent and comprehensive chronology. His chronicle was the leading authority until the 19th century, when much of his work was found to be spurious. Consequently, his reputation as a historian suffered, but the literary aspect of his work is still justly admired. His other works include two accounts of ancient Helvetia.