Christian Science began in 1866 when Mary Baker Eddy was healed of severe spinal injuries caused by a fall on ice. This healing came after she re-read one of the so-called miracles in the Bible and realised that it was not a miracle but the application of divine law, the understanding of which could bring healing now as surely as it it did in Jesus' time. She devoted three years to in-depth study of the Bible in order to understand how this could work, and began to prove, by healing others, that there is a scientific way to heal mentally - not through human will or hypnotism, nor by what we would now call the placebo effect, but through the understanding that all reality is spritual, not material.
She expanded on her discovery, first with a group of followers, and then through the publication of Science and Health in 1875. In 1879 she and her group, now calling themselves Christian Scientists resolved "To organize a church designed to commemorate the word and works of our Master, which should reinstate primitive Christianity and its lost element of healing."
This led to the founding and development of the Christian Science Movement as it is today.