Twelve mouse traps described and figured by Leonard Mascall in 16th Century England are illustrated and interpreted afresh. Special attention is given to one that is also depicted on the Merode altarpiece, an important 15th Century Dutch painting. Since Mascall's era many of his mouse traps have virtually disappeared. Others have been made more effective by various design changes, including the incorporation of small powerful helical springs and improved release mechanisms, and by the greater use of wire mesh and sheet metal.