The "Annales" were written in at least seven books, from the legendary foundation of Rome by Aeneas to Piso's own times. Like most other Roman historians, Piso devoted a significant portion of the work to mythologic times and the Regal period, covered in the first book. Then, book two likely covered the beginnings of the Republic to a milestone event such as the Fall of Veii in 396, or the Sack of Rome in 387. The third book probably described the events up to the War against Pyrrhus (280–275), or the First Punic War (264–241). The chronology for the remaining four books is lacking; Piso possibly wrote about the events down to the second half of the 2nd century by covering one generation per book. The majority of modern historians think that Piso continued his work after the last fragment dated from 146 in order to describe the events of his consulship and censorship. The existence of an 8th book has been suggested, in which Piso could have written an apologia of his political deeds during his magistracies.