protagonist

The main character, or one of the main characters, in any story, such as a literary work or drama.

A leading person in a contest; a principal performer.

An advocate or champion of a cause or course of action.

It was toward the end of the sixteenth century that the communities in Venice, Mantua, Ferrara, Padua, and Casale Monferrato, inspired by the Renaissance music, wanted to introduce some modernization into the service. The greatest protagonist of the idea was the encyclopedic Jewish scholar Leon of Modena.