Published here for the first time are Palladio's preparatory materials for an illustrated edition of Polybius' Histories alongside Palladio's material for his edition of Julius Caesar' Commentaries, (1575). Long thought to have been lost, his original Polybius has now been recomposed by drawing on three manuscript copies: the mock-up used by Palladio to plan the edition, rediscovered in the London British Library in 1977; a second copy found in Florence in 1986 and a third exemplar only very recently found in the New York Public Library. Here the reproductions of the 43 etchings for the Polybius have been accompanied by 42 etchings which Palladio dedicated to Caesar's deeds.