When looking a bit deeper past Semiotics for more appropriate methodologies I came across an approach called Iconography and Iconology. Iconography is a method developed by the art historian Erwin Panofsky. He insists that 'Iconography is that branch of history of art which concerns itself with the subject matter or meaning of works of art as opposed to their form'. This method feels very appropriate for me as it seems to specifically relate to discovering the meaning and purpose of a historical painting. This coupled with Semiology, which I have been using to decode the modern advertising images can give me a really clear method for unpacking the working processes of the artists and the connection between the two worlds.
Gillian Rose (2012) describes iconography as 'an intertextual method'. This means the viewer would have to have some grasp of the meaning behind the image to understand the signs within it. Rose goes on to say that 'Iconography is most often applied to Western figurative images and to architecture, usually from the sixteenth to the eighteenth centuries. During that period, Compendia of symbols (in the loose sense f the word) were written for both artists and for patrons. These explained the meanings of hundreds of visual motifs, allegories and personifications, and it is these compendia that art historians have consulted to produce iconographic interpretations of specific images'. So to be able to put the artwork into a historical context I would have to fully understand the visual text that the artist of the time would have been familiar with.
This certainly seems like a logical method and it is great that I have the theoretical grounding as discussed by Panofsky to give my research into the historical context a bit more structure.
Rose, Gillian. Visual Methodologies. 1st ed. Los Angeles [i.e. Thousand Oaks, Calif.]: SAGE Pubications, 2012. Print.