The large square in front of the monastery had been the ceremonial plaza of the Xiu capital, and its stones were used to build the church. On the left of the monastery façade is the great open arch of the capilla de indios, the Indian chapel. Because the Maya were accustomed to worshipping outdoors, almost all Colonial churches had outdoor Indian chapels for the use of the "converts". This large square courtyard or atrio was also the scene of the infamous auto da fe of 1562, when Landa burned the Mayan sacred books.
Robert Sharer writes in The Ancient Maya: "There are only 3 pre-Columbian Maya books, dated to the Postclassic, that have survived to the present day. They are now known as the Dresden, Madrid, and Paris codices, named for the cities where they now reside. The Dresden Codex can be characterized as a treatise on divination and astronomy. The Madrid Codex, likewise, is devoted to horoscopes and almanacs to assist the Maya priests in their divinations and ceremonies. What we have of the Paris Codex is also ritualistic; it also contains a depiction of the still poorly interpreted Maya zodiac."