In this paper a hitherto obscure Baroque artist’s monogram is deciphered. It turns out that it belongs to a master named Set Knutsson, who has used his full name as a signature on at least one preserved painting. He worked in Mid-Norway and in Jämtland in present-day Sweden from the 1630s and died in Trondheim in 1682. An attribution method important to this study is comparative style analysis based on painted script.