CALVISIUS, SETHUS (1556-1615), German chronologer, was born of a peasant family at Gorschleben in Thuringia on the 21st of February 1556. By the exercise of his musical talents he earned money enough for the start, at Helmstadt, of an university career, which the aid of a wealthy patron enabled him to continue at Leipzig. He became director of the music-school at Pforten in 1572, was transferred to Leipzig in the same capacity in 1594, and retained this post until his death on the 24th of November 1615, despite the offers successively made to him of mathematical professorships at Frankfort and Wittenberg. In his Opus Chronologicum (Leipzig, 1605, 7th ed. 1685) he expounded a system based on the records of nearly 300 eclipses. An ingenious, though ineffective, proposal for the reform of the calendar was put forward in his Elenchus Calendarii Gregoriani (Frankfort, 1612); and he published a book on music, Melodiae condendae ratio (Erfurt, 1592), still worth reading.
For details see V. Schmuck's Leichenrede (1615); J. Bertuch's Chronicon Portense (1739); F.W. E. Rost's Oratio ad renovendam S. Calvisii memoriam (1805); J G. Stallbaum's Nachrichten über die Cantoren an der Thomasschule (1842); Allgemeine Deutsche Biographie; Poggendorff's Biog.-Litterarisches Handworterbuch.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)