Thomas Edison of the Edison patent to charge a more reasonable rate for the use of the Edison patent rights and lowering the price of the electric lamp. On October 8, 1883, the US patent office ruled that Edison's patent was based on the work of William E. Sawyer and was, therefore, invalid. Litigation continued for nearly six years, until October 6, 1889, when a judge ruled that Edison's electric light improvement claim for "a filament of carbon of high resistance" was valid. To avoid a possible court battle with Joseph Swan, whose British patent had been awarded a year before Edison's,
War of the currents judge rolled back part of Westinghouse's original Gaulard Gibbs patent, stating it only covered transformers linked in series. With the help of the financier Henry Villard the Edison group of companies also went through a series of mergers: "Edison Lamp Company", a lamp manufacturer in East Newark, New Jersey; "Edison Machine Works", a manufacturer of dynamos and large electric motors in Schenectady, New York; "Bergmann & Company", a manufacturer of electric lighting fixtures, sockets, and other electric lighting devices; and "Edison Electric Light Company", the patent-holding company and the financial arm backed by J.P. Morgan and the Vanderbilt family for