The Main Cloister, or Cloister of D. João III, is the main Renaissance feature of the convent. It was built by D. João III, and is situated outside the castle walls and surrounds the nave that his father - King Manuel I - used to extend the Templar church.
The Convent's Main Cloister is part of a set of four large cloisters in which the formal structure of the convent is placed. The Main Cloister, adjacent to the conventual church, flanks the Southern façade of the Manueline nave. Its outline is different from the rest of the Castilian conventual architecture. Re-done in a Mannerist Italian Cinquecento style by Diogo de Torralva, after Castilho's passing. This cloister receives its water from the convent's aqueduct, which was designed by Fernandes Torres.