Why is Dick a nickname for Richard?

a man named richard from the 40s or 50s nick named dick because he was a Detective named Richard aka DICK RICK The name Richard is very old and it's true origins may well be lost in the depths of time past. 'Richeard' is a name from Old English where 'Ric' meant ruler and 'heard' meant hard. In those days of yore, before word-processors, everything was written down and abbreviations became common and agreed upon. Also in the 13th century rhyming slang became popular so Richard becomes Rich and eventually Rick which rhymes with Dick. Much like William - Will - Bill. 'Dick' eventually, like 'Jack', came to mean all men as in "every Tom, Dick, or Harry". Shakespeare uses "every Tom, Dick, or Francis" in Henry IV Part I.