There’s nothing humble about humble pie or about eating humble pie. In fact, Old English and Middle English texts from 1330 onward referred to the heart, liver and entrails of animals as umbles. Umbles were used as an ingredient in pies, and the first printed record of umble pie was found in a diary by a Samuel Pepys on July 5, 1662 wherein he wrote:
“I having some venison given me a day or two ago, and so I had a shoulder roasted, another baked, and the umbles baked in a pie, and all very well done.”
A little over a year later, on July 8, 1663, he wrote:
“Mrs Turner came in and did bring us an Umble-pie hot out of her oven, extraordinarily good.”
Since umble pie was often eaten by those who came from humble situations, and seeing that humble means offered in a spirit of deference or submission, it’s easy to see that over time, eating humble pie came to mean acting submissively and apologetically, especially when admitting to having made a mistake.
Historically Speaking 