William K. Warren (1897–1990) founded the Warren Petroleum Corporation of Delaware in 1922. He and his company (headquartered in Tulsa) soon became specialists in the production and marketing of liquefied petroleum gas, a byproduct of petroleum refining and natural gas purification. Warren sold his company to Gulf Oil Corporation in 1953 for $450 million, the largest such merger in the energy industry up to that time. Warren then turned his attention to philanthropy and established the Saint Francis Hospital system in Tulsa.