Art history is the study of art. An art historian is a person who studies the history of art, and then writes about it or teaches about it so that other people can learn about this subject as well.
The first person to become an art historian was Giorgio Vasari. He lived in Florence during the Renaissance, at a time when there were many famous artists alive. Vasari was an artist himself. He decided to write down all the stories that were told in Florence about the many different artists who had made the city famous. He included biographies of several other artists from Northern Italy as well. When all the information was collected and the biographies written, he published them in 1568 in a book called Lives of the Artists. Because of this book, art students today have a lot of information about artists such as Leonardo, Michelangelo, Titian and their works.