The painting is entitled The Calling of St. Matthew. Caravaggio immortalizes the moment when Christ invites the tax collector to become his disciple. A ray of light from the right is projected onto the wall, which is how you must examine the painting, starting from Christ's invitation to the surprised Matthew who points a finger at his chest. As you can see, light dominates the scene and subdivides it into two registers: the lower shadow is full of figures, while the top is illuminated by the ray entering from the window.