Templo y Exconvento de San Mateo Apóstol

From the plaza in Atlatlahucan, San Mateo looks more like a castle than a church: heavy walls crowned with battlements and buttresses that end in points, borrowed straight from medieval building. Augustinian friars raised it under Fray Jerónimo de San Sebastián and Fray Jorge de Ávila. Spanish Wikipedia dates the work to 1535-1567, while other sources put the founding around 1570, when the town was still a dependency of Totolapan. In time the parish passed from the friars to the diocesan clergy, and in 1994 it joined the World Heritage list with the other monasteries on the slopes of Popocatépetl.

It is one of the most complete sets on the route: church, friary, walled atrium, a three-arched open chapel in the northwest corner, a pilgrims' portal and four posa chapels, two of which survive. The façade is nearly bare. The arched doorway has no carving, and above it sit a choir window and a clock added in the late 19th century. Inside, the single barrel-vaulted nave has Mudéjar geometric decoration and two frescoes, a Last Supper and a family tree of the Augustinian order. The cloister, by contrast, is plain and austere.

After the UNESCO listing the convent orchards were brought back into use, and they now grow avocados and other crops whose sale helps pay for upkeep. The 2017 earthquake closed the church; in 2023 INAH reported it restored and back in use for worship, with work on the friary still under way. The parish is also known for keeping the Latin Mass, with the priest facing the altar and Gregorian chant, so if a service is on, go in quietly. Saint Matthew's feast day is 21 September.