This is Nicola D'Inverno, Sargent's valet who frequently modeled for him. Nicola was Italian born, but it is unknown how Sargent met him. Was he one of those gondoliers Sargent picked up in Venice? Was he also Sargent's lover? He worked for and lived with Sargent for 24 years and even posed as a woman for one painting. Hard to imagine them not being sexually involved.