If there is any truth in the popular belief to which we shall presently allude, that diamonds promote the mutual affection of husband and wife, then indeed the great yellow stone had need of its charm in the case of Ferdinand's son and successor, Cosimo III. This luckless prince was married to Marguerite Louise d'Orleans, niece of Louis XIV., a young lady of flighty fancies and obstinate willfulness. Being deeply attached to her cousin of Lorraine, she was only induced to give her hand to the heir of Tuscany on the threat of imprisonment in a convent. She was married in 1660 and made her state entry into Florence amid unparalleled splendor. Immediately afterwards the courts of Europe rang with the quarrels of the newly-wedded pair. The Pope of Rome, the King of France, mother, sisters, aunts, ambassadors, bishops, cardinals, lady's maids, each in turn interfered with the object of restoring harmony, and each in turn ignominiously failed. Here surely was work for the diamond had it been possessed of its reputed power. During this time and for many years afterwards, the diamond about which we write was known as the "Florentine" or "Grand Tuscan." It was the chief jewel in the treasure-house of the Medici, and no doubt filled a conspicuous place in the pageants of the grand-ducal court. The Florentine sovereigns were not wealthy, but upon state occasions they made extraordinary displays which sometimes deceived foreigners visiting among them into a false idea of their affluence. A wedding was always a favorite occasion upon which to show off their finery. For example, at the marriage of Violante de Bavière with the son of Cosimo III., a magnificence was displayed such as was never before seen even in Florence. The bride sat on a car studded with gems. Her father-in-law with his crown, no doubt containing the great diamond, upon his head, met her at the gate of San Gallo and escorted her to the palace. This princess dying childless, the throne was occupied by Giovan-Gaston, another son of Cosimo III. and the flighty Marguerite. He likewise left no heirs, so with his death in 1737 terminated the great house of Medici. Giovan-Gaston was succeeded on the grand-ducal throne by Francis Stephen of Lorraine, who was forced much against his inclination to change his paternal duchy of Lorraine for that of Tuscany. He was married to Maria Theresa, archduchess of Austria, afterwards so famous as the Empress-queen who fought valiantly against Frederick the Great. By the will of Giovan-Gaston dei Medici all the statues, books, pictures and jewels of his palace were "to remain forever at Florence as public property for the benefit of the people and the attraction of foreign visitors," and none were to be removed from out of the Grand Duchy.