The youngest of eight, Mary Ann was born in Quito, Ecuador, which had been brought under Spanish control in 1534. She joined the Secular Franciscans and led a life of prayer and penance at home, leaving her parents house only to go to church and to perform some work of charity. She established in Quito a clinic and a school for Africans and indigenous Americans. When a plague broke out, she nursed the sick and died shortly thereafter.
She was canonized by Pope Pius XII in 1950.