Cathedral School for Boys in Dallas opened in September 1946 out of the reorganization of the Terrill School for Boys in August 1946. The last headmaster, John D. Kirby, became the assistant headmaster of Cathedral. The reorganization of the Terrill School for Boys into the Cathedral School for Boys also included the assets from an Episcopal boys school in Austin called St. Luke’s School, which operated there from 1941 to 1946. St. Luke’s founder and headmaster, Walter W. Littell, joined the Cathedral School for Boys staff as an administrator and teacher. The school opened in the same location as Terrill at St. Matthew’s Episcopal Church on Ross Avenue. Terrill had suffered a decline for more than a decade, partly because of the Great Depression, partly because of World War II, and partly because of competition from Texas Country Day School since 1933. Terrill had been the highest standard of educational excellence in Dallas since its founding in 1906, so its demise, while gradual, was nonetheless a shock to the Dallas community and marked the end of an era.
The headmaster of Cathedral was the Right Reverend Charles Avery Mason, bishop of the Episcopal Diocese in Dallas. He had sought an opportunity to develop an institution that was equal parts college preparatory schooling and religious studies and jumped at the chance to take over the Terrill assets and infrastructure, made all the more convenient since it was already in an Episcopal church. Reverend Mason was the visionary who helped launch Cathedral School from the ashes of Terrill.
Cathedral School struggled from the start, however, and never really hit its stride during its brief four-year existence. Cathedral really ended up being a rebranded version of the declining Terrill School that it had replaced. The school had a full array of classes and extra-curricular activities, and although it offered athletics, with only twelve seniors in the school by the start of the 1949 school year, the Gargoyles struggled to be competitive.
Reverend Mason handed over his headmaster duties to Rev. Alfred L. Alley in 1948, but nothing seemed to work, and the school continued to barely operate. The board, still led by Mason, decided that it did not want to close its doors and actively sought a merger with Texas Country Day School. By late 1949 the schools announced the merger of the two schools to become St. Mark’s School of Texas with the start of the 1950–51 academic year at the existing Texas Country Day School campus at 10600 Preston Road. Members of both schools’ boards jointly sat on the new St. Mark’s board. The Dallas Morning News reported that TCD board member George L. McGregor said, “A city which supports a great university [Southern Methodist University] and a fine girls’ school [Hockaday School for Girls] is now able to unite in the support of an equally fine boys’ school.”
Writing the Cathedral School’s farewell to the community in the school’s 1950 yearbook, The Gargoyle, Reverend Mason likened the impending merger as a graduation of itself into something bigger. “St. Mark’s School is as close to my heart as the Cathedral School has been,” he wrote, and he implored the graduates and returning students to “transfer your devotion to this new school” as St. Mark’s “will be worthy of the same support you have given the Cathedral School.”
In the 2010s St. Mark’s School of Texas continued to thrive as one of the premier preparatory schools in the country, and Cathedral School was an integral part of that history. Rt. Rev. C. Avery Mason, Episcopal bishop for twenty-four years in Dallas, passed away in 1970.