The sunken ship, made almost entirely of wood and measuring 18 metres by 4.5 metres, has lain for years untouched near the coastline of Salento, in the southern tip of the Puglia region, La Stampa reported.
The wreck was found in the Porto Cesareo Marine Protected Area, where human activity is restricted in order to conserve the area's natural resources.
Pasquale De Braco, a fisherman and adviser to the protected area, notified local authorities of its presence, and divers were sent to investigate.
Because of the boat's proximity to the medieval fishing village of Porto Cesareo, it could “explain significant aspects of the coastline in medieval times and contribute to the historical reconstruction of the area,” said Cristiano Alfonso, an underwater archaeologist from Salento University's Department of Cultural Heritage, who carried out the initial assessment.
Paolo D'Ambrosio, president of the Porto Cesareo Marine Protected Area, said in a statement: “We are very happy and excited not only by the important discovery of the wreck, but also by the productive collaboration between the Department of Archaeology at the University of Salento and Porto Cesareo Marine Protected Area.”
Eight hundred years is a long time, but in 2012 a 2,000-year-old shipwreck - one of the best preserved - was found off the coast of Liguria.
And in 2009 five pristine Roman shipwrecks were found near the small island of Ventotene, part of an archipelago off Italy's west coast.