The titular figure sits on the far left with his head bowed and a light shining on him from the upper right, and a man in the middle of the table points at him in surprise.  
Located in the Contarelli Chapel in the Church of San Luigi dei Francesi in Rome, the only object visible in the background of this work is a window of a tavern.  The titular figure sits on the far left with his head bowed and a light shining on him from the upper right, and a man in the middle of the table points at him in surprise.  Jesus, mostly hidden behind St. Peter on the far right, also points at the titular figure, indicating him to follow in, FTP, what great tenebrist painting by Caravaggio?
Located in the Contarelli Chapel in the Church of San Luigi dei Francesi in Rome, the only object visible in the background of this work is a window of a tavern.  
The Calling of St. Matthew