Information:  - George David Cummins (December 11, 1822  June 26, 1876) was an American bishop and founder of the Reformed Episcopal Church.  - The Reformed Episcopal Church (REC) is a Anglican Christian church of evangelical Episcopalian heritage. It was founded in 1873 in New York City by George David Cummins, formerly a bishop of the Protestant Episcopal Church.   - A Christian (or ) is a person who follows or adheres to Christianity, an Abrahamic, monotheistic religion based on the life and teachings of Jesus Christ. "Christian" derives from the Koine Greek word "Christós" (), a translation of the Biblical Hebrew term "mashiach".  - Robert Livingston Rudolph ( December 29 , 1865 -- September 16 , 1930 ) was a bishop of the Reformed Episcopal Church in the early twentieth century . He was the first bishop to be raised with the church . Rudolph also served as Professor of Dogmatic Theology and Christian Ethics at the Theological Seminary of the Reformed Episcopal Church in Philadelphia for twenty - seven years before his death . Together Rudolph and his son , Robert Knight Rudolph , trained men for the gospel ministry at this institution for a total of seventy - four years . Rudolph was widely recognized as an outstanding preacher , teacher , scholar and bishop .  - Robert Knight Rudolph (June 8, 1906  July 14, 1986) was an American Reformed Episcopal minister and theologian. He served as Professor of Systematic Theology and Christian Ethics at the Theological Seminary of the Reformed Episcopal Church in Philadelphia for forty-nine years before his retirement in 1981. Together Rudolph and his father trained men for the gospel ministry at this institution for a total of seventy-four years. Rudolph was known for his strict adherence to Calvinism and presuppositional apologetics.  - Calvinism (also called the Reformed tradition, Reformed Christianity, Reformed Protestantism, or the Reformed faith) is a major branch of Protestantism which follows the theological tradition and the forms of Christian practice that were developed by John Calvin and other Reformation-era theologians.    Given the information above, choose from the list below the object entity that exhibits the relation 'occupation' with the subject 'robert livingston rudolph'.  Choices: - bishop  - founder  - knight  - major  - professor  - religion  - theologian  - translation
A:
theologian