Caravaggio was born in Milan, his given name was Michelangelo Merisi. A short time later, in an attempt to avoid The Plague which has wreaking havoc in Milan at the time, his family moved to the town where he grew up and was later named after, Caravaggio. After his apprenticeship, he became the stereotypical self-destructive artist. Fights and violent rages fueled by alcohol and quite possibly a bipolar disorder, regularly lent credence to his personal motto: Nec Spe, Nec Metu, (Without Hope, Without Fear). He preferred the company of thugs and whores and often used them as models in his religious paintings. While he didn't invent it, he is most famous for pushing the envelope of the chiaroscuro technique, which is the use of bright lights and and solid darks to create a dramatic effect. I don't remember where I heard this, but one of the most fascinating things about Caravaggio is that he didn't sketch or draw, he simply started painting. That's akin to building a house without a plan. Below are a few examples of his work, and of course, you can Google his name and find tons more.
The Crucifixion of Saint Peter. 1601
David With the Head of Goliath. 1609-1610.
Judith Beheading Holofernes. 1598-1599.
Death of the Virgin. 1601-1606.