Despite the knowledge of the existence of oil reserves in Venezuela for centuries, the first oil wells of significance were not drilled until the early 1910s. In 1908, Juan Vicente Gómez replaced his ailing predecessor, Cipriano Castro, as the president of Venezuela. Over the next few years, Gómez granted several concessions to explore, produce, and refine oil. Most of these oil concessions were granted to his closest friends, and they in turn passed them on to foreign oil companies that could actually develop them