A 1955 analysis of paint samples from an Italian painting found evidence of cobalt, suggesting the use of cobalt blue, a pigment not used in Europe before 1804  The painting was thus deemed to have been produced sometime after 1804
A 2009 analysis also found cobalt, but that analysis suggested that the painting might have been produced before 1804
New information that came to light in the 1990s suggested that cobalt blue was used only rarely in Italy in the years immediately following 1804.