I said that a knowledge of chant is necessary for all, and would like to explain that.

Years ago I studied music theory and counterpoint and the Bach chorales.

That year, no one explained why...or I was just not paying attention.

Studying counterpoint today using both modern texts and historic documents, the first thing you run into is a list of what intervals may be written and which are forbidden. We are talking about intervals in the harmonic sense, but also in the writing of leaps.

What I found surprising is that the rules about interval leaps are the same rules that govern the composition of Gregorian Chant, which are still in use today.