This one guitar has quite the legacy and back story.
It starts, of course, with Martin. The first of their designs to really step away from classical guitar-inspired shapes and builds, the OM was debuted in 1929 for Perry Bechtel, a bandleader who was looking for something loud enough to replace the banjo. Though their other models were being adapted for steel strings, the guitar for Perry was the first to be designed with steel strings as the starting point, ultimately informing the bracing and construction. Martin foreman John Deichman started with the 000 body but gave it a slimmer 14-fret neck and a long scale length, making it the first 14-fret steel-string flattop ever made. These features would prove so popular that Martin would soon make 14-fret versions of many of their models, including the dreadnought which soon eclipsed the OM in popularity for players looking for a loud stage guitar.