The history of releases goes back to the ancient Chinese and the Turks, who used a thumb type release to set arrow flight distance records which were not equaled until modern times. The advent of the modern release began in the 1960's, but these releases were shot on command and were of limited help for increasing accuracy or helping with a target panic problem. The change that revolutionized freestyle archery occurred in the late 1960's with the introduction of the plastic ledge type of release.
Best I could do