a German music theorist, composer, chronologer, astronomer, and teacher of the late Renaissance. He published a book on music, Melodiae condendae ratio (Erfurt, 1592). He composed choral pieces including Unser Leben währet siebzig Jahr. Calvisius was also a significant astronomer: in his Opus Chronologicum (Leipzig, 1605, 7th ed. 1685) he expounded a system based on the records of nearly 300 eclipses.
