The original chapel dates back probably to 11th century, built right after the conquest of the city from the Moors in 1064, just prior to the foundation of Portugal. It is dedicated to St. Michael, like all Portuguese Royal Chapels, because of it (religious) role in defeating the forces of evil.
The current layout is the direct result of the 16th century renovations under the patronage of King Manuel I, whose decorative style has its patent mark on the side door, one of the simplest and most beautiful of its kind.
The interior decoration was carried out over the 16th and 18th centuries and works by artists like Simão Rodrigues, Simão Ferreira, Joaquim Ferreira Bernardes and Francisco Araujo can be appreciated all throughout the building. The majestic pipe organ by Friar Manuel of St. Benedict (1733), with over 2000 tubes, is still in use today.