In 1890, after studying Christian Science about four years, Hanna left his legal practice to devote himself to "the Cause of Christian Science", although he had no plan of how to proceed. In May 1890, there was a three-day meeting of Mary Baker Eddy's students held in New York City, the fifth annual meeting of the National Christian Science Association and the Hannas decided to attend. While there, Septimus Hanna was invited to take charge of a society of Christian Scientists in Scranton, Pennsylvania. After visiting Scranton, he accepted the invitation, marking the beginning of his career in Christian Science.