Poul Henningsen developed the PH 5 in 1958 in response to constant changes made to the shape and size of incandescent bulbs by bulb manufacturers, naming it after the size of the pendant’s main shade, which is 50 cm in diameter. When the lamp was introduced, he wrote, typically daringly, about how he had lost faith in whether the manufacturers of incandescent light bulbs would ever learn to consider common sense or have the consumer’s best interests at heart: “I have accepted fate, and with Louis Poulsen´s permission I have designed a PH fixture, which can be used with any kind of light source, Christmas lights and 100 W metal filament bulbs.