Poggio also found a copy of Julius Frontinus de Aquæductis, and eight books of Firmicus’s treatise on the mathematics, lying neglected and forgotten in the archives of the monastery of Monte Cassino; and at the instance of Niccolo Niccoli he prevailed upon the governors of that religious house, to allow him to convey these manuscripts to his own residence, for the purpose of decyphering and copying them. After he had transcribed Frontinus with his own hand, he returned the original manuscript to the library where it had been discovered.[95] He also procured at Cologne a copy of Petronius Arbiter, a small fragment of which author he had before discovered in Britain. By his exertions also the entire work of Columella was brought to light, of which only fragments had been known to the earlier scholars. For the preservation of Calpurnius’s Bucolic also, the republic of letters is indebted to the sagacious diligence of Poggio.[96] In a long and elaborate letter which Poggio received from Francesco Barbaro, and which bears the date of June 7th, 1417, this learned patrician congratulates his correspondent on the glory which he had acquired by his labours in the cause of learning, and ascribes to the unremitted diligence of his investigations, the recovery of the works of the following authors, in addition to others which have been already enumerated; Manilius, Lucius Septimius, Caper, Eutychius, and Probus. From this letter of Barbaro, it appears, that the republic of letters had expected that Poggio would have been materially assisted in his inquiries after the relics of ancient literature by Bartolomeo di Montepulciano, but that in consequence of the ill state of his associate’s health, he was under the necessity of taking upon himself almost the entire conduct and trouble of the research.