Although the seminary existed prior to 1844, Mercersburg Theology began in earnest in that year with the hiring of Philip Schaff to join John Williamson Nevin on staff at the seminary. Schaff sparked off controversy with his inaugural address, which was later published as "Principle of Protestantism". This led to a series of articles written against Professor Schaff’s view by fellow RCUS pastor Joseph Berg. Several other magazines attacked Schaff and Nevin over their controversial position concerning the relation of the Reformed churches to the Roman Catholic Church. The RCUS was divided on the issue, as the Philadelphia Classis condemned Schaff’s theology, while the East Pennsylvania Classis defended it. The Synod took up the issue in 1845 and cleared Schaff and "Principle of Protestantism" by a vote of 37 to 3. This marked the only time Schaff was brought before the Synod on heresy charges; the Synod ruled that further complaints had to be registered with the Board of Visitors (trustees) of the Mercersburg Seminary, which never allowed any more complaints to go before the Synod for trial.