Through history, the systems of economic support for scientists and their work have been important determinants of the character and pace of scientific research. The ancient foundations of the sciences were driven by practical and religious concerns and or the pursuit of philosophy more generally. From the Middle Ages until the Age of Enlightenment, scholars sought various forms of noble and religious patronage or funded their own work through medical practice. In the 18th and 19th centuries, many disciplines began to professionalize, and both government-sponsored "prizes" and the first research professorships at universities drove scientific investigation. In the 20th century, a variety of sources, including government organizations, military funding, patent profits, corporate sponsorship