Designed by João de Castilho in the Manueline style, the shrine-like portal is large, 32 m high and 12 m wide, extending up two stories. It includes gables, pinnacles, many carved figures standing under a baldachin in exquisitely carved niches, around a statue of Henry the Navigator (center jamb figure). The tympanum features scenes from the life of Saint Jerome. The Madonna of Belém stands on a pedestal on top of the archivolt.

Established near Toledo in 1374, the Hieronymite Order soon became popular in Spain and Portugal, and in 1415 it numbered 25 houses. Prince Henry the Navigator (1394-1460) founded S Maria de Belém, a chapel of the Order of Christ, for mariners. Soon after his accession Manuel I (reigned 1495-1521) decided to build a grand monastery for the Hieronymite Order, which would continue to serve mariners as well as providing a burial place for the king. It also commemorated Vasco da Gama's successful return from India and was built with money from the spice trade; he is buried in the church. This project drained funds from the work at Batalha, which remained unfinished. The complex includes the church, monastery, sacristy, and refectory. It is a UNESCO World Heritage Site.