Moving from Ernesto Buonaiuti’s autobiography, Il pellegrino di Roma. La generazione dell’esodo (1945 and especially 1964), the essay analyses the close relationship – on the level of personal memory, and not of general history – be- tween Buonaiuti priest and Buonaiuti professor. The problem of the role played by Antonio Labriola in the formation of the young Buonaiuti is crucial. The future author of Pellegrino di Roma was influenced by Labriola’s lectures on the philosophy of history in the years 1900-1901 or 1901-1902; he did not listen in person, perhaps only read later and certainly misinterpreted Labriola’s 1896 inaugural lecture L’Università e la libertà della scienza