Prior to the Conquest, the small caves in the Chalma area were thought to be holy, and all caves came under Tezcatlipoca, the "Smoking Mirror," the representative of the Mexica night.
The aspect of Tezcatlipoca associated with caves was Oxtoteotl (also: Ostocteotl, Ostoteotl, Ostoctheotl) which has been translated as “the Dark Lord of the Cave,“ though there is little agreement on how to translate this term.
Francisco de Florencia, in his 1689 chronicle of the place (the earliest written source available on the subject) suggested the name Ostoc Teotl, but also said that his indigenous sources were unsure of the identity of the deity.
In one of the caves, it was said to be a large, man-sized, black, cylindrical idol of Oxtoteotl with reputed magical and healing powers.
Oxtoteotl was a god of human destiny or of night, sometimes appearing as a jaguar or with the god of war, depending on different oral traditions.
Those who made pilgrimage to the deity walked for days in the surrounding mountains, wearing flowers and carrying incense burners.
After arriving to the site, they bathed in the nearby river fed by a sacred spring and drank holy water before entering the cave.
There were also signs that worship of this deity included human sacrifice.

In approximately 1537, Augustinians, including Brothers Sebastian de Tolentino and Nicolas Perea came to evangelize the Malinalco region of which Chalma is part.
From there, the story has a number of versions.
Most state that after learning about and perhaps seeing the rites associated with the worship of Oxtoteotl, Tolentino and Perea worked to evangelize here, urging the local people to destroy the idol.
Then, three days later, the friars returned to destroy the idol themselves, but instead found a life-sized image of a crucified Christ in the space that the idol, which was found in pieces on the ground, previously occupied.
Upon seeing the image, the indigenous people are said to have fallen down in “apostolic piety,” which allowed for the conversion of the people of this area.

A less-popular version of the story states that a muleteer was looking for one of his animals when he found the Black Christ in one of the caves.

The cave in which the Christ image was found became a very popular Christian pilgrimage site starting from the 16th century.
In 1643, a primitive church was constructed in a nearby plain.
The Augustinian order administered the cult and chapel for many years, before deciding to construct a monastery and buildings to house the pilgrims who came to worship.
By the end of the Colonial period, the complex was known as the Royal Convent and Sanctuary of Our Lord Jesus Christ and Saint Michael of the Caves of Chalma.

At many indigenous shrines in Mexico, the previous sacred images were replaced with Christian ones, occasionally made of a corn paste called “tatzingueni” using a technique developed by Vasco de Quiroga, and a number of these figures still exist.
 After the supposed appearance of the Black Christ figure, the Augustinian friars proclaimed a miracle had occurred in the cave, word of which spread and even included the idea that the area had been freed of predatory animals.
Prior to the Conquest, the small caves in the Chalma area were thought to be holy, and all caves came under Tezcatlipoca, the "Smoking Mirror," the representative of the Mexica night. The aspect of Tezcatlipoca associated with caves was Oxtoteotl (also: Ostocteotl, Ostoteotl, Ostoctheotl) which has been translated as “the Dark Lord of the Cave,“ though there is little agreement on how to translate this term. Francisco de Florencia, in his 1689 chronicle of the place (the earliest written source available on the subject) suggested the name Ostoc Teotl, but also said that his indigenous sources were unsure of the identity of the deity. In one of the caves, it was said to be a large, man-sized, black, cylindrical idol of Oxtoteotl with reputed magical and healing powers. Oxtoteotl was a god of human destiny or of night, sometimes appearing as a jaguar or with the god of war, depending on different oral traditions. Those who made pilgrimage to the deity walked for days in the surrounding mountains, wearing flowers and carrying incense burners. After arriving to the site, they bathed in the nearby river fed by a sacred spring and drank holy water before entering the cave. There were also signs that worship of this deity included human sacrifice.
In approximately 1537, Augustinians, including Brothers Sebastian de Tolentino and Nicolas Perea came to evangelize the Malinalco region of which Chalma is part. From there, the story has a number of versions. Most state that after learning about and perhaps seeing the rites associated with the worship of Oxtoteotl, Tolentino and Perea worked to evangelize here, urging the local people to destroy the idol. Then, three days later, the friars returned to destroy the idol themselves, but instead found a life-sized image of a crucified Christ in the space that the idol, which was found in pieces on the ground, previously occupied. Upon seeing the image, the indigenous people are said to have fallen down in “apostolic piety,” which allowed for the conversion of the people of this area.
A less-popular version of the story states that a muleteer was looking for one of his animals when he found the Black Christ in one of the caves.
The cave in which the Christ image was found became a very popular Christian pilgrimage site starting from the 16th century. In 1643, a primitive church was constructed in a nearby plain. The Augustinian order administered the cult and chapel for many years, before deciding to construct a monastery and buildings to house the pilgrims who came to worship. By the end of the Colonial period, the complex was known as the Royal Convent and Sanctuary of Our Lord Jesus Christ and Saint Michael of the Caves of Chalma.
At many indigenous shrines in Mexico, the previous sacred images were replaced with Christian ones, occasionally made of a corn paste called “tatzingueni” using a technique developed by Vasco de Quiroga, and a number of these figures still exist.  After the supposed appearance of the Black Christ figure, the Augustinian friars proclaimed a miracle had occurred in the cave, word of which spread and even included the idea that the area had been freed of predatory animals.
Chalma, Malinalco