With few reliable maps, no navigation equipment save for a compass and the stars, and no means of communicating with anyone out of visual range, ocean voyages were a lot more treacherous in centuries past. At least one of those problems was solved with the invention of radio telegraphs: for the first time ships could signal distress from miles away in the ocean. The only problem remained in establishing some international standard in the calls.

On this day. July 1, in 1908, based on the agreement Radiotelegraphic Conference held in Berlin, the “SOS” Morse code became the internationally-recognized symbol for a general call for help to all stations.

The code was not chosen for an abbreviation to anything like “Save Our Ship” or “Save Our Souls,” but rather for the distinctness of the code: three dots, three dashes, three dots. There could be no mistaking it for anything else. Those advantages notwithstanding, the code was not uniformly and instantaneously adapted: when the Titanic went down in April of 1912, the ship broadcasted an S.O.S. distress call along with a still-common C.Q.D., that meant essentially the same thing.