638.
[48] Besides the great work of Bonanni, _Templi Vaticani Historia_, I may refer my readers to the atlas volume of _Illustrations, Architectural and Pictorial, of the Genius of Michael Angelo Buonarroti_, compiled by Mr.
Harford (Colnaghi, 1857).

Plates 1 to 7 of that work are devoted to the plans of S.Peter's.

Plate 4 is specially interesting, since it represents in one view the old basilica and the design of Bramante, together with those of Antonio di S.Gallo and Michael Angelo.
[49] The subterranean vaults of S.Peter's contain mere fragments of tombs, some precious as historical records, some valuable as works of art, swept together pell-mell from the ruins of the old basilica.
[50] See the original letter to Ammanati, published from the Archivio Buonarroti, by Signor Milanesi, p.

535.
[51] I am far from meaning that the earlier architects had not been guided by ancient authors.

Alberti's _Treatise on the Art of Building_ is a sufficient proof of their study of Vitruvius, and we know that Fabio Calvi translated that writer into Italian for Raphael.