An 16th century construction of a circular plan dedicated to S. Gregório Nazianzeno, theologian who proved the divinity of Jesus.

The rectangular Manueline portal stands out, soberly decorated and sheltered by the galilee that surrounds three sides of the chapel. With an octagonal plan, surmounted by a Renaissance style dome. The 18th century tile panels originate from the Convent of Trinas in Lisbon.