PORTRAIT IDENTIFICATION OF HISTORICAL FIGURES
99 percent of the time the value of a painting depends on who painted it. The market pays for names. The bigger the name the higher the value.
There is an exception to this situation; portraits.
The value of a portrait depends on how big of a name the sitter has and on how rare his portraits are.
Regardless of who painted it, if a portrait is an authentic original likeness of a popular figure, it is worth millions.