Theologians are those individuals who systematically and rationally study religion. Training is usually received at a university or a divinity school. Theology can be separate from religious studies, and has a long tradition that dates back to the before the earliest days of Christianity.
Augustine of Hippo first defined theology as discussion concerning the Divinity (God). Later thinkers described theology as the science of God. There are numerous aspects to theology, including philosophy, history, scripture and ethnography that seek to explain, defend, understand or promote any number of religious topics.
Plato's Academy in Athens devoted study to theological matters, and the study of religion also occurred in China in the 2nd century BC, and in the Islamic world beginning in the 10th century CE. Most modern understandings of theology emerged out of universities in Western Europe during the later Middle Ages. Institutions such as the University of Paris and Oxford were respected centers of theological study.
Beginning in the 19th century, theology became an instrumental part of professional ministerial training. Many of the first colleges in America, including Harvard and Yale, were founded as places to train theologians and ministers. Theologians continue to remain part of academia around the world, despite the rise of secular and atheist criticism.