Lady Mary O'Brien (died 1686) (d. 1686) Parents Mary Brereton Henry O'Brien, 5th Earl of Thomond Children William Cokayne Charles Cokayne Mary Cokayne Brien Cokayne, 2nd Viscount Cullen Siblings Lady Honora O'Brien Lady Anne O'Brien Lady Margaret O'Brien Lady Elizabeth O'Brien Partners George Blount Charles Cokayne, 1st Viscount Cullen