Mulled wine is called "mulled" because the word "mulled" originally meant "heated" or "spiced." The term comes from the Old English word "mull," which meant "to muddle" or "to mix."
In the case of mulled wine, it refers to the process of heating the wine and mixing it with spices and other ingredients to create a warm, flavourful beverage. The practice of heating wine and adding spices dates back to ancient times, when the Romans would add spices and honey to their wine to make it more palatable. In medieval Europe, mulled wine was a popular drink during the winter months, and it was often served at holiday celebrations and winter festivals. Today, it is still enjoyed in many countries as a cosy, comforting drink during the colder months and a very important drink at Christmas time.