Help! I can't find any information on the origin of the idiom/expression: Put your foot in your mouth. Please help me!

Question

"put one`s foot in one`s mouth

- get into trouble by saying something embarassing or rude

My colleague put his foot in his mouth when he told everyone that he didn't like the new manager."

idiomconnection com/head.html

http://www.idiomsite.com/

This site gives the history of the idiom