Throughout his travels, he had abandoned
Christianity for
Islam, and he was requested by
Pope Eugene IV, as a
penance, to relate his travels to the papal secretary
Poggio Bracciolini. Poggio's recording of Niccolò's account, made in
1439, constitute one of the best accounts of the East by a 15th century traveler. They were included in the Book IV of his "DeVarietate Fortunae" (The Vicissitudes of Fortune).
Niccolò Da Conti's travels, which first circulated in
manuscript form, are said to have profoundly influenced the European geographical understanding of the areas around the
Indian Ocean during the middle of the 15th century. They were the first accounts to detail the
Sunda Islands and
Spice Islands since the accounts of
Marco Polo. His accounts probably encouraged the
European travels of exploration of the end of the century.
He also influenced 15th century cartography, as can be seen on the
Genoese Map (1447-1457), and in the work of the mapmaker
Fra Mauro, whose influential
Fra Mauro map (1457) offered one of the clearest depiction of the
Old World. In these two maps, many new location names, and several verbatim descriptions, were taken directly from Da Conti's account. The "trustworthy source" whom Fra Mauro quoted in writing in his map about the travels of a "
junk from
India" (lit. "Zoncho de India"), beyond the
Cape of Good Hope into the
Atlantic Ocean around
1420, confirming that it was possible to sail around
Africa through the south, is thought to have been Niccolò Da Conti himself.
In his descriptions of Eastern Asia, Da Conti matter-of-factly describes huge
junks of about 2,000 tons, more than four times the size of
16th century Western
galleons:
:
They make ships larger than ours, about 2,000 tons in size, with five sails and as many masts. The lower part is made of three decks, so as to better resist storms, which occur frequently. These ships are separated into several compartments, so that if one is touched during a storm, the others remain intact."
Niccolò Da Conti's book was used by several explorers and travels writers, such as
Ludovico di Varthema (1510), and
Antonio Pigafetta, who traveled around the world with
Magellan's expedition.