Henry Benedict Stuart, Cardinal Duke of York, the Last of the Royal Stuarts
Francesco Saverio Cardinal de Zelada by Anton Raphael Mengs
Louis René Édouard Cardinal de Rohan of "affair of the necklace"-fame
Silvio Cardinal Valenti Gonzaga, patron of the arts and manic collector.
Giovanni Andrea Cardinal Archetti
I don't know who that is. The face looks familiar somehow. Anybody?