[3] Soon after arriving at the university he had his first encounter with the future anti-fascist journalist Piero Gobetti, in the context of a competition in which they were both involved for a student-bursary from Turin's "Collegio delle province".
His dissertation was supervised by Vittorio Cian and concerned the vernacular work of the Franciscan Umbrian friar Jacopone da Todi.
[3] During 1924 Sapegno edited for publication a selection of philosophical pamphlets by Thomas Aquinas as part of a series being produced under the leadership of Giovanni Papini by Rocco Carabba's publishing business.
[2] Towards the end of 1924 he relocated to Ferrara (roughly equidistant between Bologna and Padua) where for some years he taught "literary subjects" - principally Italian and History - in various secondary schools.
[2] Throughout this period he was also building his profile among Italian intellectuals with regular scholarly contributions to specialist journals such as "Archivum Romanicum", "Leonardo", "La Nuova Italia", "Pegaso" and "Civiltà Moderna".
[2] In terms of establishing his reputation within the academic community, the volume "Il Trecento" ("The fourteenth century"), written in 1933 and published in 1934, was probably more important than any of those learned literary reviews on the output of contemporary literati, however.
The book was published by Valardi in Milan as part of the "Storia letteraria d’Italia" ("History of Italian Literature") series, replacing an earlier volume on the topic which had appeared in 1902.
The replacement from Natalino Sapegno was well received by scholars: thanks, in particular, to a favourable review published in 1934 by Giulio Bertoni of the "Société de linguistique romane", won for its author one of the (four) 1934 prizes awarded by the Accademia d’Italia.
[9] In 1936 he participated in the nationwide competition organised by the University of Messina to fa the vacancy that had arisen at the for an extraordinary professorship in Italian literature.
[3] Public government support for the appointment might lead to the assumption that Sapegno might not remain in post after the fall of fascism in 1943, but in fact he continued to teach at the Sapienza till 1976.
During the early years of his long incumbency he taught courses on Poliziano, Dante, Boccaccio, Ariosto and Pulci, thereby cementing his reputation as an authority on the fourteenth and fifteenth century Italian literary dawn.
The uncompromisingly idealistic liberal anti-fascist philosophy of Croce would always remain as his starting point; but he also came increasingly under the influence of Gramsci, whereby in his own writings he moved towards a singular fusion of Historicism and Marxism which, in terms of traditional Anglo-American thought patterns, defies easy pigeon-holing.
Sources highlight, in particular, his collaboration with Emilio Cecchi on the "History of Italian Literature" ("Storia della letteratura italiana"), published by Garzanti in nine volumes between 1966 and 1969.