When dealing with missionary endeavors abroad most writers tend to concentrate on the evangelical aspect. However, missionaries have played a much more extensive role than this. In the case of Iran, the evangelical impact of the missionary effort was minimal in comparison to both the medical and educational branches of their work. In spite of their original intent of revitalizing the native Christianity, it was through their educators and doctors that the missionaries had their greatest influence on 19th and 20th century Iran. For centuries Iran had been relatively isolated from the outside world and its advances. Such conditions were to change as other countries acquired an interest in Iran. The British viewed Iran as a buffer for their Indian Empire and the Russians sought territorial gains. As a matter of fact, it was the Perso-Russian Wars (1813 and 1827) that suddenly awakened the Iranian government to the power of the Western nations. In order to compete, in order to survive, Iran, too, had to master Western technology. Yet this transition was to require almost a century. The 19th century witnessed the beginning of change within Iran and the American missionaries played a role in this process. Because of the lack of educational opportunities within Iran, as well as the need for medical care, the missionaries provided such services until the government was able to do so. They maintained this role for approximately one hundred years, during which time they made innumerable contributions. However, these contributions were not made without opposition. The introduction of the new force infringed upon the status quo. Many Iranians felt their position threatened. The missionary presence aroused the antagonism not only of the hierarchy of the local Christian churches, but also local officials, the Muslim ulama and the Persian government. This conflict was further intensified by the fact that the Christian minorities began to look to the missionaries, rather than their own leaders, to mediate disputes. This, is addition to their role of educator and doctor, the missionary also become arbitrator on behalf of the Nestorians. In tracing the development of the American missionary activities in Iran from their origins in 1834 through the year 1941, it becomes apparent that this was a century of changing political climate and social conditions within the country. The year 1941 is not an arbitrary date but was chosen because at this point the government had taken over all ' foreign operated schools and had established laws that limited the medical practice of the missionaries. Such measures are indicative 'of the effort made by Reza Shah Pahlavi, prior to his abdication in 1941, to consolidate power and decrease foreign control. As a result of the continuing efforts of Reza Shah to concentrate power in his hands, the missionaries' role in education and medicine was absorbed by the State.