William O'Brien, 4th Earl of Inchiquin British earl and politician (1700–1777) Parents Mary Villiers William O'Brien, 3rd Earl of Inchiquin Children Augustus O'Brien George O'Brien Murrough O'Brien William O'Brien Mary O'Brien, 3rd Countess of Orkney Siblings Lady Henrietta O'Brien Lady Mary O'Brien Charles O'Brien James O'Brien Partners Mary Moore Anne O'Brien, 2nd Countess of Orkney
