This essay on the Adoration of the Kings in the Snow, in the Oskar Reinhart Collection 'Am Römerholz', Winterthur, examines the conception and execution of this small masterpiece by Pieter Bruegel the Elder. It discusses the surprising findings of dendrochronology, which link it with several other small-scale paintings by the artist, and examines in detail the underdrawing, paint layers, brushwork and handling. It examines the evidence for a lost model drawing of the composition and the hypothesis that Brueghel the Younger's copies probably reproduce the father's initial design as it appeared on this lost sheet.