One of the city's most interesting sights, this convent was built between 1654 and about 1815 on the site of a battle in which a miraculous appearance of Santiago (St James) apparently led to the Otomí surrender to the conquistadors and Christianity. Emperor Maximilian had his headquarters here while under siege in Querétaro from March to May 1867. After his surrender and subsequent death sentence, he was jailed here while awaiting the firing squad.
Today it's used as a religious school. You must visit with a guide – you wait at the entrance until a group has formed – although tours are in Spanish. The site's main legend is the growth of the Árbol de la Cruz, an ancient tree in the convent's garden, whose thorns are in the shape of crosses. This miracle was the result of a walking stick stuck in the earth by a pious friar in 1697.
You can visit the attached church without a guide or entry fee. The entrance to the convent is to the right of the church.