The quality of both is high, so it also seems unlikely that one painting is a student piece made after the other. The compositions are very close, but hardly exact, suggesting that pure forgery was not a motive. In fact, the painting on the right is by Caravaggio, now in the Vatican Galleries in Rome. The one on the left is a free copy after it by Peter Paul Rubens. It now hangs in the National Gallery of Canada in Ottawa.
Art historians recognize both works as the legitimate creations of great artists.
Rubens made a number of such copies, particularly after Titian, whom he greatly admired, both while he was a student learning his trade and later when he was a mature artist managing a large and commercially highly successful studio. Art historians would not be surprised or shocked by this. After all, from time immemorial, artists have adapted works by their contemporaries and by older artists for a variety of reasons. Michelangelo copied Massaccio and Schongauer, Vasari relates how Del Sarto's copy of Raphael's portrait of Leo X fooled even Giulio Romano, who had a share in the original. Rembrandt sketched Raphael's Castiglione ,Van Gogh copied Rembrandt, Millet, and Delacroix, and Picasso frequently copied or made versions of works from the past.