The Triumph of Death is one of only two known cases of Bruegel's sons copying the same large-format composition after their father. In this case, examination reveals that the copyists were not able to study the original pianting de visu. New high-resolution scientific imagery of Pieter Bruegel the Elder's original version in the Museo Nacional del Prado, Madrid, Pieter Brueghel the Younger's version in the Kunstmuseum Basel, and Jan Brueghel the Elder's version in the Universalmuseum Joanneum, Graz, elucidates not only the modus operandi of the copyists, but also the hidden working processes of the creator, Bruegel the Elder. The study also highlights the respective underdrawing and painting styles of father and sons, as well as Jan Brueghel's ingenious updating of the composition.