According to Why Christmas, mince pies, like Christmas Puddings, was originally filled with meat, such as lamb, rather than the dried fruits and spices mixed as they are today. They were also first made in an oval shape to represent the manger that Jesus slept in as a baby, with the top representing his swaddling clothes. Sometimes they even had a ‘pastry baby Jesus’ on the top!
During the Stuart and Georgian times, in the UK, mince pies were a status symbol at Christmas. Very rich people liked to show off at their Christmas parties by having pies made in different shapes (like stars, crescents, hearts, tears, & flowers); the fancy-shaped pies could often fit together a bit like a jigsaw! They also looked like the ‘knot gardens’ that were popular during those periods. Having pies like this meant you were rich and could afford to employ the best, and most expensive, pastry cooks.
Now they are normally made in a round shape and are eaten hot or cold.
A custom from the middle ages says that if you eat a mince pie every day from Christmas to Twelfth Night (evening of the 5th of January) you will have happiness for the next 12 months!