Dr Irwin was one of the physicians appointed to attend the Jacobite court in Rome and he was well-known in social circles there. Scottish architect Robert Adam met him about fifteen years after this portrait was painted and described him as: “a very sensible, clever old man of near eighty years who every day drinks his four or five bottles of wine, has a flow of spirits meet for forty years and does not look sixty.” This painting is one of several painted by Dupra of men who were closely associated with the Jacobites whilst they were in exile. As with the other paintings in this series, Dupra left an inscription on the back of the canvas giving the date and referencing the Jacobite cause.