One of possibly the earliest, simplest and most ingenious safety catches was that designed by Frank Clarke for his last version Titan pistol, circa 1923. The safety was automatically applied once the gun was cocked and was released by squeezing the grip while taking aim. Yes, the Titans were rather primitive guns, but you have to admit that a safety that needed no knobs to turn or buttons to press and just did the job without any involvement on the part of the shooter was pretty clever.