Perhaps all of Mariana’s spiritual gifts would have remained a secret but for her ultimate sacrifice. In the year 1646, the city of Quito, capital of Ecuador, was being ravaged by many scourges on account of the sins of its Catholic population. Volcanic eruptions, earthquakes, and terrible diseases were decimating the population. More than fourteen thousand people had been killed and many buildings were destroyed in the quakes. When the volcano Pinchincha erupted after being dormant for more than eighty years, the people began to accept the truth that their sins were the cause.
Father Alonso de Rojas, pastor of the Jesuit church, offered himself publicly, as he preached from the pulpit, to be a propitiatory victim and asking God that he might die to save the people from the punishment they deserved. After his sermon, Mariana, who had been sitting right in front of the church, calmly rose from her seat and announced in a loud clear voice that she would take the place of Father Rojas because he was a good priest and much more needed in Quito than she was. She then asked Our Lord to accept her offering “in defense of her country, her compatriots, and her kindred” and that she “might be chastised for everything in the city which deserved chastisement.” Upon arriving at her home, she was immediately struck with a mortal illness to which she succumbed within two months. During her final suffering the earthquakes stopped, the volcano quieted, and the plagues died out.
All of Quito prayed for Mariana’s recovery, realizing what a great sacrifice she had made for them. God accepted their prayers as repentance, but Mariana’s soul was taken to paradise to be with her Beloved forever on Ascension Thursday, May 26, 1645. When she breathed her last, her body fell over on the dirt floor, and on that very spot a white lily sprang forth from the earth that had received some of the blood that was still moist on her garments. This is why she is known as the Lily of Quito.Source: https://catholicism.org/saint-mariana-de-jesus.html