St. John's College was founded in 1887 with the establishment of the “Select School” for young men at the Catholic presbytery, Holy Redeemer Cathedral in Belize City. The founder of St. John's College was Fr. Cassian Gillett, S.J., one of four British Jesuit priests, who arrived in Belize in the 1880s. The school opened with 12 day-students and two boarders. According to the 1897 prospectus, the school's mission was “to afford the youth of the Colony, and the neighboring Republics, the means of obtaining a solid mental and moral training.” It added that Belize needed “a school of Higher Studies so that our youth would not have to go abroad for preparation for university work.”