CALVISIUS, SETHUS German musician and chronologer, was born at Gorschleben, in Thuringia, on Feb. 21, 1556, and died at Leipzig, where he was director of the school of music, on Nov. 24, 1615. In his Opus Chronologicum (Leipzig, 1605, 7th ed. 1685) he expounded a system based on the records of nearly 30o eclipses. He put forward an ingenious proposal for the reform of the calendar in his Elenchus Calendarii Gregoriani (Frankfort, 1612). His principal work in music is Exercitationes musicae (1600-1 i) .
See K. Benndorf, Sethus Calvisius als Musiktheoretiker (1894).