Casilda was the daughter of a Muslim leader in Toledo, Spain, in the 10th century. She was raised as a Muslim and showed special kindness to Christian prisoners. She became ill as a young woman but was not convinced that any of the local Arab doctors could cure her. So she made a pilgrimage to the shrine of San Vicenzo in northern Spain. Like so many other people who made their way there—many of them suffering from hemorrhages—Casilda sought the healing waters of the shrine. We’re uncertain what brought her to the shrine, but we do know that she left it relieved of illness.
In response, she became a Christian and lived a life of solitude and penance not far from the miraculous spring. It’s said that she lived to be 100 years old. Her death likely occurred around the year 1050.
Tensions between Muslims and Christians have often existed throughout history, sometimes resulting in bloody conflict. Through her quiet, simple life Casilda served her Creator—first in one faith, then another. – americancatholic.org