Plaza Mariana is the current name for the area in Northern Mexico City south of Tepeyac Hill. The area has long been a cultural center even before the arrival of the Spanish. The scale of the area has grown over the years, especially in the last few decades, but continues to be an area of cultural importance.
Before the arrival of the Spanish and with them Catholicism, some Aztec groups used this area to worship the mother goddess Tonantzin, going as far as building a temple at the base of Tepeyac Hill. Some time after the arrival of the Spanish the temple was destroyed and a chapel put in its place, though the exact date of the chapel's construction is debated.
Historical records from between 1556 and 1575 make references to the chapel but make no mention of its exact construction date or more importantly to the story that makes up the other argument for an exact date. While the historical evidence points to sometime between 1555 and 1556, the Catholic Church has long supported the legend of Juan Diego and the Lady of Guadalupe as an explanation of when and why the chapel was built.
The story says that in December 1531, the Lady of Guadalupe appeared to a mestizo Christian named Juan Diego near Tepeyac Hill. She told him to tell the bishop Juan de Zumárraga to build a chapel at the base of the hill. Zumárraga did not believe Juan Diego and wanted proof that it was the true Lady of Guadalupe that had appeared to him. She gave Juan Diego fresh roses to carry in his tilma and show to Zumárraga. When Juan Diego opened his tilma the roses spilled out and an image of the Lady of Guadalupe appeared on the cloth. Zumárraga swiftly requisitioned the construction of a church. So while historical records point to a date around 1555, the story supported by the church points to an earlier date between 1531 and 1532. Interestingly, the story itself didn't appear in print until 1648 in a book by a priest named Miguel Sanchez. When asked why this was the first time anyone had heard of this story, he said that people had simply forgotten the story. While the date of the first chapel is still disputed, the other buildings at Plaza Mariana are much less of a mystery.
Some time after the first chapel's construction it was replaced by another chapel that is today called the Ex-Parroquia de Indios. Inside of this chapel you can see the foundation of the original chapel. More outward dedication to the Juan Diego legend began in 1695 with the beginning of the Templo Expiatorio a Cristo Rey, also called the Old Basilica or the Sinking Church. Construction was completed in 1709 and was the first to house the tilma with the image of Our Lady of Guadalupe. The church reached its peak in 1904 when it was given the status of Basilica. In 1921, a bomb inside of a flower pot exploded damaging the building interior but the tilma was not damaged. As the years went on the foundation of the Basilica began to sink into the ground. Rather than demolishing the Basilica, it was restored and a new Basilica built next door to replace it. Between 1974 and 1976, today's main attraction, the Basílica de Nuestra Señora de Guadalupe, was built and now houses the original tilma from the Juan Diego story.