From the display:

Depictions like this one of a boy blowing on a burning ember were popular among European painters studying illumination. Artists such as Michelangelo and El Greco used this subject to showcase their skills at imitating nature, particularly the fleeting reflections of firelight. After spending several successful years working in Rome, Gerrit van Honthorst brought this theme back to the Netherlands, where it was appreciated by sophisticated collectors who recognized its origins in an ancient Roman text.