On August 10, 1937, the United States Patent Office recognizes the electric guitar—the instrument that revolutionized jazz, blues and country music and made the later rise of rock and roll possible—with the award of Patent #2,089.171. It went to George D. Beauchamp, a musician-turned-inventor for an electrified instrument known as the Rickenbacker Frying Pan.

Versatile, inexpensive and relatively easy to play, the acoustic guitar was a staple of American rural music in the early 20th century, particularly black rural music such as the blues. But a significant physical limitation made it a poor fit in ensembles made up of brass, woodwind and orchestral string instruments: The acoustic guitar was simply too quiet. What transformed the guitar and its place in popular music, and eventually transformed popular music itself, was the development of a method for transforming the sound of a vibrating guitar string into an electrical signal that could be amplified and re-converted into audible sound at a much greater volume. Enter George Beauchamp.

With partner Adolph Rickenbacher in the Electro String Instrument Corporation of Los Angeles, California, Beauchamp spent more than five years pursuing his patent on the Frying Pan. It was a process delayed by several areas of concern, including the electric guitar’s reliance on an engineering innovation that dated to the 19th century. When a vibrating string is placed within a magnetic field, it is possible to “pick up” the sound waves created by that string’s vibrations and convert those waves into electric current. Replace the word “string” with the word “membrane” in that sentence, however, and you also have a description of how a telephone works. For this reason, Beauchamp’s patent application had to be revised multiple times to clarify which of his individual claims were truly novel and which were merely new applications of existing patents.

On August 10, 1937, the Patent Office approved the majority of Beachamp’s claims—primarily those relating to the unique design of the Frying Pan’s “pickup,” a heavy electromagnet that surrounded the base of the steel strings like a bracelet rather than sitting below them as on a modern electric guitar. Unfortunately for the Electro String Corporation, Beauchamp’s specific invention had long since been obsolesced by the innovations of various competitors, rendering the patent awarded on this day in 1937 an item of greater historical importance than economic value.