The idea of establishing an Ursuline school in Boston originated with Father John Thayer, a Massachusetts native who converted to Roman Catholicism after a transformative experience in Rome in 1793. Thayer died in 1815, having recruited several nuns in Ireland for the project, and donated his estate to the cause. In 1820, the Most Reverend Jean-Louis Lefebvre de Cheverus, bishop of the newly created diocese of Boston, oversaw the opening of the convent in the rectory of the Boston cathedral. A school for girls was set up in the convent, intended to educate the area's poor. Approximately 100 students were eventually enrolled. The early years of the school were plagued by tuberculosis, which claimed the lives of the convent's first mother superior and several of the sisters. A new leader, Mother Mary Edmond St. George, was recruited from the Ursuline convent in Trois Rivieres, Quebec, where the Boston nuns had trained.