A baker’s dozen means a group of 13 items instead of 12.

Medieval Law: In 1266, King Henry III of England enacted the Assize of Bread and Ale, a law that strictly regulated the weight and price of bread loaves.

Severe Penalties: Bakers who sold underweight bread faced harsh punishments, including heavy fines, public humiliation in the pillory, or physical flogging.

The “Vantage” Loaf: Because individual loaves naturally varied in weight during baking, bakers added an extra 13th loaf (known as a “vantage loaf” or “in-bread”) to every 12 sold to guarantee they were never accidentally short-weighted.