One of the pupils of the famous tenor Tito Schipa (1889 -1965) was Stefan Zucker, who went on to found the Bel Canto Society.  Zucker’s lessons with Schipa cost $12. Zucker described his lessons with Schipa like this:

The routine began with scales [on the five alphabetic vowels, Italian a, e, i, o, u] with him (Schipa) at the piano. If the student ran out of support before a scale was over Schipa didn’t seem to notice or care.  He never mentioned breathing or placement…He didn’t interfere.

The only thing he would say to each student was that the vowel “ah” should be pronounced with a very broad mouth (bright, never like “awe”)…I studied with him without covering a single note. He never suggested I do so. The subject didn’t arise.

These lessons seem to infer that for Schipa (one of the great tenors of the early 20th century), the primary concern of vocal training was the Italian VOWEL and the purity of the pronunciation of each vowel.  His instructions on teaching voice was to exercise it on the various vowels, and the breath ‘support’ would naturally come as the muscles and coordinations in the throat musculature grew more complete and stronger.

This would be in total accordance with the “Larynx first, Breath second” approach that Francesco Lamperti talked about in the mid-1800s.

In the video below, Pavarotti says something rather interesting: the fact that Schipa doesn’t have a large voice. Callas said the same of the bel canto training, that it would not necessarily make a voice large, but PENETRATING.