The relationship between Pieter Brueghel the Younger's Massacre of the Innocents in Sibiu and Pieter Bruegel the Elder's original version in Hampton Court is examined as part of a techical study of the copy's techniques and materials. The authenticity of its atypical signature is affirmed. The oak panel with its maker's mark, black chalk underdrawing, preparatory layers, use of the blue pigment smalt and aspects of painterly handling are discussed in relation to other works examined by the same artist. The likely copying process is also considered.