Dominic Mancini was an Italian who visited England in 1482, left in 1483 and left behind an account of the events he witnessed. He called it: De Occupatione Regni Anglie per Riccardum Tercium (The Occupation of the Throne of England by Richard III).

Mancini's purpose was probably to spy on behalf of Angelo Cato, Archbishop of Vienne, one of the counselors of King Louis XI of France and also his doctor and astrologer. Although some historians think Mancini arrived in England at the end of 1482, others believe he got there just before Edward IV died (9 April 1483). He returned to France in July some time between the coronation of Richard III on (6 July 1483), before the princes disappeared, and the delivery of his report in December. It is not clear how much English Mancini understood, and much of what was happening in England while he was there had to be translated to him. A possible source was Dr John Argentine, an opponent of Richard who became a member of Henry Tudor's court once he became Henry VII and who spoke Italian. Argentine was the doctor who was treating the elder prince, Edward V, while he was in the Tower and is one of the last persons known to have seen the two princes alive.

Mancini's report was lost for centuries but was discovered in the Municipal Library in Lille, France, in 1934. Mancini never met King Richard, but he did not hesitate to repeat the gossip that was current about the activities of the royal family. He did not say that Richard had murdered his nephews, merely that there was a "suspicion" they had been done away with. Guillaume de Rochefort, Chancellor of France, who repeated the rumour in the Estates-General in Tours (France) in January 1484, adding that Richard III had "massacred" the princes and then been given the crown "by the will of the people", may have obtained his information from Mancini's report. This intelligence was used as an excuse by the French for assisting Henry Tudor's invasion.