From the Annals of Big Oil –  In 1911, the Magnolia Petroleum Company was founded.  The MPC was an unincorporated joint-stock association comprised of several other companies including primarily the John Sealy Company of Galveston. In 1931, Magnolia became an affiliate of Socony-Vacuum Oil Company. The Magnolia Petroleum Company merged with Socony Mobil Oil Company in 1959. Its operations became part of Mobil Oil Company, an operating division of Socony Mobil.