_Io: Grollierii et amicorum_ reads as a very pretty and unselfish sentiment, but it requires some explanation. Mons. Grolier did not allow his treasured volumes to leave his possession. Those who were privileged to enjoy his friendship, were permitted to consult his books; they had no choice, however, but to do so in the spacious salons of Mons. Grolier, after partaking of his hospitality. On the death of Grolier, in 1565, his valuable collection became the property of Emeric de Vic, Keeper of the Seals, from whom it passed to his son. On his death, this library, which had been the pride of three generations of book-lovers, was sold and dispersed in 1676. Some of the principal books came into the possession of such well-known collectors as Paul Petau, de Thou, and the Chancellor P. Séguier; they have been well preserved till the present day, but they contain no book-plates belonging to Grolier. Paul Petau was a councillor in the Parliament of Paris. He formed the nucleus of a library, rich in early French and Latin MSS., and was also an enthusiastic collector of coins and antiquities. On his death, in 1613, he left the whole of his collections to his son Alexander, who not only succeeded to his public offices, but also inherited his cultivated tastes for art and literature. Paul Petau had his books handsomely bound, with his arms stamped on the sides. His arms are thus emblazoned by French heraldists: _Ecartelé_: au 1 et 4, d’azur, à 3 roses d’argent, au chef-d’or chargé d’une aigle issante éployée de sable; au 2 et 3, d’argent, à la croix pattée de gueules. _Devise_: Non est mortale quod opto. It will thus be seen that the arms are precisely the same as those carried by his son Alexander on his book-plate, the motto alone being changed in the latter to “_Moribus Antiquis_.” M. Poulet-Malassis makes a curious misstatement in describing this ex-libris, for he asserts that the shield bears quarterly the arms of _Alexander_ Petau and of his wife. It may be that M. Poulet-Malassis intended to say the arms of _Paul_ Petau and of his wife, for Paul, the father, certainly carried these arms, as did Alexander afterwards, with the statement that he was the son of Paul. Now Paul Petau could not have carried the arms of his son’s wife. The shield rests on a mosaic pavement, on which are reproduced in alternate squares the three principal charges, namely, the eagle issuant, the three roses, and the cross pattée (see plate, page 69). On the death of Alexander Petau his MSS. were purchased by Queen Christina of Sweden, who bequeathed them to the Vatican Library. His printed books were sold at the Hague in 1722, with those of François Mansart. “Catalogue des bibliothèques de feu _M.M. Alexandre Pétau_, conseiller au Parlement de Paris, et _François Mansart_, intendant des bâtiments de France.” La Haye, A. de Hondt, 1722.