If you ever walk through the lovely, old streets of Leipzig in Germany, you might pass by a large St. Thomas Church (the Thomaskirche). That monumental building is the exact place where Johann Sebastian Bach worked. And he lived right next to it. Today, people all over the world think of Bach as one of the greatest musical geniuses who ever lived. When you look at his image in old paintings, he looks like a serious, strict man wearing a big white wig. But who was that man?