Abstract
This article outlines the main theoretical ideas of Johannes Lippius, the prominent German musical scientist of the 17th century. During his short lifetime he created a number of treatises, some of them were influential for the next generations of learned musicians. A wide range of problems is considered in the works of Lippius: from musical aesthetics and theology to specific questions of composition. To the most interesting and important ideas of Lippius belongs especially the concept of the “harmonic triad”, which is discussed here in its historical context.