High Quality Content by WIKIPEDIA articles! Waite returned home to Iowa and, after six months of college studies, launched into an active business career. His business experience, under the guidance and help of his elder brothers, Frank and L.E. Phillips, moved swiftly from a short period of coal mining in Iowa to oil operations, in 1906, centered around Bartlesville, Oklahoma His brothers created the business which became known as Phillips Petroleum Company. In 1914 Phillips sold his oil interests to his elder brothers. He started out on his own as an individual oil producer, refiner and marketer. His fully integrated and extensive oil operations lasted almost 40 years. After 1918, he had his headquarters in Tulsa, Oklahoma. While in Tulsa, Phillips built several office complexes, such as the Philtower and Philcade. He also had a mansion built, the 72-room Italian Renaissance-style Villa Philbrook. In 1938 during the Great Depression, Phillips donated his immense home to the city of Tulsa, which adapted it into the Philbrook Museum of Art. Each of these buildings has been listed on the National Register of Historic Places.