A historian is someone who studies and tells stories about what happened in the past. Imagine you are reading a really long book about a family's life. You learn where they lived, what jobs they had, what they ate, and how they spent their free time. A historian does something similar but instead of just one family, they study and tell stories about many people and places from long ago. They read books, letters, and other things that people wrote a long time ago so they can understand what happened in the past. Then, they share their knowledge with others so they can learn about the past too. It's like being a detective who is trying to solve a really old mystery.