In 1866, Mrs. Lavinia Jannetta Horton Ryves, and her son, William Henry Ryves, appeared before the English courts in support of one of the most extraordinary petitions on record. Taking advantage of the Legitimacy Declaration Act, they alleged that Mrs. Ryves was the legitimate daughter of John Thomas Serres and Olive his wife, and that the mother of Mrs. Ryves was the legitimate daughter of Henry Frederick Duke of Cumberland and Olive Wilmot, his wife, who were married by Dr. Wilmot, at the Grosvenor Square mansion of Lord Archer, on the 4th of March, 1767. They also asserted that Mrs. Ryves had been lawfully married to her husband, and that her son was legitimate; and asked the judges to pronounce that the original marriage between the Duke of Cumberland and Olive Wilmot was legal; that their child Olive, who afterwards became Mrs. Serres, was legitimate; that their grandchild Mrs. Ryves had been lawfully married to her husband; and that consequently the younger petitioner was their legitimate son and heir. The Attorney-General (Sir Roundell Palmer) filed an answer denying the legality of the Cumberland marriage, or that Mrs. Serres was the legitimate daughter of the duke. There was no dispute as to the fact that the younger petitioner, W.H. Ryves, was the legitimate son of his father and mother. The case was heard before Lord Chief-Justice Cockburn, Lord Chief-Baron Pollock, Sir James Wilde, and a special jury. The opening speech of the counsel for the claimant revealed a story which was very marvellous, but which, without the strongest corroborative testimony, was scarcely likely to be admitted to be true. According to his showing Olive Wilmot was the daughter of Dr. James Wilmot, a country clergyman, and fellow of a college at Oxford. During his college _curriculum_ this divine had made the acquaintance of Count Poniatowski, who afterwards became King of Poland, and had been introduced by him to his sister. The enamoured and beautiful Polish princess fell in love with Wilmot and married him, and the result of their union was a daughter, who grew up to rival her mother's beauty. The fact of the marriage and the existence of the daughter were, however, carefully kept from the outer world, and especially from Oxford, where Dr. Wilmot retained his fellowship. The girl grew to the age of sweet seventeen, and, in 1767, met the Duke of Cumberland, the younger brother of George III., at the house of Lord Archer, in Grosvenor Square. After a short courtship, the duke was said to have married her--the marriage having been celebrated by her father on the 4th of March, 1767, at nine o'clock in the evening. Two formal certificates of the marriage were drawn up and signed by Dr. Wilmot and by Lord Brooke (afterwards Lord Warwick) and J. Addey, who were present at it; and these certificates were verified by the signatures of Lord Chatham and Mr. Dunning (afterwards Lord Ashburton). These documents were put in evidence. The Duke of Cumberland and Olive