The modern history of Christianity in Thailand begins with the work of missionaries or foreign religious workers. In the 1550s the Portuguese mercenaries and their chaplain arrived in Ayutthaya. By 1660, the Vicariate Apostolic of Siam was established under the leadership particularly of Portuguese and French fathers. Protestants appeared in the new capital of Bangkok in 1828 through the Missionary society representative, Jacob Tomlin and the Missionary society representative, Karl Augustinus Gützlaff and after them, American Board of Commissioners for Foreign Missions representative, David Abeel followed by Rev. Jesse Casswell and Dr. Dan Beach Bradley. These two both switched affiliations to the American Missionary Association (AMA) in 1848 over their support for the Finney revival emphasis on "perfectionism" that the Congregationalist parent organization found unorthodox, effectively ending the work of the ABCFM in Siam.