In the late 1870s gaslight was the primary means used to light residential homes and most businesses. Electric lighting had been conceived of decades earlier, but no one had been able to produce electric lighting in a safe, feasible, affordable manner. A number of inventors were working on this problem, but Thomas Edison was the first to develop a long-lasting, practical light bulb. His patent application for that light bulb was filed with the United States Patent Office on November 4, 1879, and his patent was granted on January 27, 1880.