In 1725, i.e. 300 years ago, Johann Joseph Fux released his magnum opus. It was not an oratorio, a requiem or any kind of composition but a treatise on composition itself and specifically the defining aspect of the Baroque Era; the counterpoint.
His book Gradus ad Parnassum is considered the pinnacle guide to the counterpoint. According to the legend, both Johann Sebastian Bach and Leopold Mozart gave it to their sons to study the counterpoint. There is some irony here because Bach's son, Carl Philip Emmanuel Bach, is considered the man who influenced the transition from the Baroque to the Classical era, when the prevalence of the counterpoint diminished. Same for Mozart, who was himself the pinnacle of the classical era.
Even today, JS Bach and Vivaldi are considered among the greatest masters and their art of the counterpoint is central to their achievements.