What was the focus of the artist masaccio?

Massaccio, a painter during the Italian Renaisance, created many famous works of art. These include paintings done at the Brancacci chapel: The expulsion from the Garden of Eden and The Tribute Money. Another famous work of his was the "PIsa Alterpiece" which was later dimantled and dispersed. Other notable works include "Potrait of A Young Man", "Madonna with Child and Angel" and "St. Paul".