Niumimansa. Cadamosto encountered that hostility on his first expedition of 1455. But on his second trip, in 1456, opposition fell away for some reason, and he managed to become the first European (along with Antoniotto Usodimare and their anonymous companions) to sail up the Gambia River. It is uncertain what caused this change of attitude from one year to the next – a new Niumimansa? A shift in senegambian politics? The unreliable Diogo Gomes later boasted that he sailed to the Gambia sometime between 1456 and 1458 and single-handedly negotiated a peace with the Niumimansa, although this is likely exaggerated.) Once they opened the Gambia River, Cadamosto and Usodimare led the next great leap of Henrican discoveries in Africa – Cape Verde islands, the Casamance River, Cape Roxo, Cacheu River and finally the Geba River and Bissagos Islands. The length of coast they discovered in 1456 was the greatest leap in the Portuguese era of discoveries since 1446. Much the same coast would be covered again by Diogo Gomes around 1458 (possibly as early as 1456, probably sent by Henry as a follow up to Cadamosto's report) and 1462. Cadamosto's furthest marker would only really be surpassed by Pedro de Sintra in 1461–62. Return to Venice After his return in 1456, Cadamosto continued to live in Lagos for many years, suggesting he must have continued to engage, directly or indirectly, in West African commerce. It is not known whether Cadamosto himself made any further trips down the African coast. Cadamosto bluntly states that there were no other voyages of exploratory significance by anyone after 1456, until the expedition of Pedro de Sintra in 1462. Cadamosto acquired the details of that expedition from Sintra's clerk upon its return. Cadamosto's patron, Prince Henry the Navigator, died in November 1460, and the monopoly on African trade reverted to the Portuguese crown and its operations were gradually transferred from Lagos to Lisbon. Probably seeing no future for himself in the new order, Cadamosto left Portugal and returned to Venice in February 1463. Cadamosto is believed to have brought notes, logs and several nautical maps with him. Cadamosto used these to compose his famous Navigationi sometime in the mid-1460s. The Navigazioni, besides generally hailing the Portuguese discoveries and lionizing Prince Henry, provided detailed accounts of three expeditions – his own voyages of 1455 and 1456, and the voyage of Pedro de Sintra in 1462. He