In medieval England, pots and dishes were made from a clay known as “pygg,” and it was common practice to save spare change in a kitchen pot.
Around 1600, an English potter who was unfamiliar with this custom was asked to make a pygg bank.
He misunderstood, and thought it was supposed to be a clay vessel in the shape of the animal.
The end result was a clay pig with a slot in its back.
The piggy bank was born and is still popular today.