New Hempstead, New York (known informally as the Brick Church) and the other in Ramapo, New Jersey were united as a single church with the Rev. James D. Demarest as their pastor since September 21, 1809. Demarest joined the secession movement, and on June 11, 1824, he led 68 members of the two congregations, including two elders, out of the Dutch Reformed Church. The people who seceded from the Brick Church established themselves as a new independent congregation in Monsey and were therefore referred to as the Seceder church. Its first elders were Garret Serven (Sarven), Joseph Iserman, Teunis VanHouten, and Peter C. VanHouten, and its deacons were Peter Serven (Sarven), Stephen VanOrden, and Cornelius Springsteen. One of the members was Jacob Felter, a veteran of the War of 1812 buried in the Historic Monsey Cemetery. On April 26, 1825, the Monsey Church petitioned Classis Hackensack of the newly formed True Reformed Dutch Church to receive them into care, and this was granted. The Monsey Church was established as the True Reformed Dutch Church of West New Hempstead. Worship was held in a building at the corner of Maple Avenue and Saddle River Road, adjacent to the Historic Monsey Cemetery, and a surviving church record book dated September 8, 1827, records to the sale of pews to the officers and members of the church. James D. Demarest continued as pastor of both the Monsey Church and the Ramapo, New Jersey church for many years. With many more churches than trained pastors, it was commonly the case that pastors would oversee multiple congregations, rotating among them on successive Sundays. One of the deacons at Monsey toward the end of the Rev. James D. Demarest's pastorate was John Yeury de Baun, born in Monsey in 1827. In 1852, when de Baun was 25 years old, he was accepted by Classis Hackensack as a student in theology, under the tutelage of Demarest and the Rev. Abram Van Houten. During the period of –, Van Houten took over the pastorate of Monsey from Demarest, until de Baun had completed his studies in theology in 1855 and called to be the pastor of both the Ramapo, New Jersey and the Monsey churches. De Baun preached alternate Sundays at Ramapo, New Jersey and Monsey until 1860, when he accepted a call to pastor the churches in Hackensack and English Neighborhood, New Jersey. Shortly after being organized