(WHTM) — Leaving milk and cookies out for Santa Claus before going to bed on Christmas Eve is a tradition for many families.

Santa isn’t very picky as he will eat any cookie and drink any milk, but why do we leave milk and cookies out for Santa?

According to Rent-A-Christmas, there are three theories behind this Christmas tradition:

The Dutch Connection

In the past, the Netherlands would celebrate Christmas on Dec. 6. So on Dec. 5, the kids would leave out their shoes and wake up to their shoes being filled with treats. This would change over time and eventually lead to children leaving out cookies and milk for Santa instead.

The Great Depression Connection

In a time when many families struggled, Christmas was a bright spot. The families would ask their children to leave out milk and cookies for Santa to thank him for bringing gifts.

The Dairy Connection

Similar to the Christmas Pickle tradition, this theory mentions that leaving milk and cookies out for Santa was a marketing ploy. The dairy industry was struggling in the early 20th century, so how do you raise sales, well by marketing that Santa drinks milk with his cookies.

Milk and cookies aren’t the only foods that are left for Santa, according to History. In the United Kingdom and Australia, sherry and mince pies are left out. In Sweden, rice porridge is left out. In Ireland, a pint of Guinness and cookie are left out. In France, a glass of wine is left out. And in Germany, letters are left out instead of treats.

When leaving out milk and cookies this Christmas, don’t forget to leave some carrots for his reindeer to enjoy for their long journey.