Christianity is the religious and cultural phenomenon that has most influenced the Western world and Estonia. Church history and the interpretation of Christian theology or religion in various churches have always been and are the main field of research of the Faculty of Religion. The church history deals with the texts of the early Christianity and the Church Fathers as well as the Reformation. The main focus is on Estonia's diverse church history in the 20th century, including the reasons for the development of Estonia's modern ecclesiastical landscape, and the Estonian and Baltic Orthodox Church and spirituality over the past 150 years.