Vandino and Ugolino Vivaldi

Vandino (sometimes Vadino or Guido) and Ugolino Vivaldi (sometimes Ugolino de Vivaldo) (fl. 1291) were two brothers and Genoese explorers and merchants.
History.
Vandino and Ugolino Vivaldi were connected with the first known expedition in search of an ocean way from Europe to India (Cape Route). Ugolino, with his brother Guido or Vandino Vivaldo, was in command of this expedition of two galleys, which he had organized in conjunction with Tedisio Doria, and which left Genoa in May 1291 with the purpose of going to India "by the Ocean Sea" and bringing back useful things for trade. Planned primarily for commerce, the enterprise also aimed at proselytism. Two Franciscan friars accompanied Ugolino. The galleys were well armed and sailed down the Morocco coast to a place called Gozora (Cape Nun), in 28º 47' N., after which nothing more was heard of them. The expedition of the Vivaldi brothers was one of the first recorded voyages that sailed out from the Mediterranean into the Atlantic since the Fall of the Western Roman Empire in the 5th century AD.
It is believed that when Lancelotto Malocello set sail from Genoa in 1312, he did so in order to search for Vandino and Ugolino Vivaldi. Malocello ended up remaining on the island that is named for him, Lanzarote, one of the Canary Islands, for more than two decades.
Early in the 14th century, Sorleone de Vivaldo, son of Ugolino, undertook a series of distant wanderings in search of his father and uncle, and even reached, it is said, Mogadishu on the Somali coast, but was prevented by the King of Mogadishu from going to Aksum, because the road to the collapsed ancient kingdom was no longer secure. In 1455 another Genoese seaman, Antoniotto Uso di Mare, sailing with Cadamosto in the service of Prince Henry the Navigator of Portugal, claimed to have met, near the mouth of the Gambia, with the last descendant of the survivors of the Vivaldo expedition. The two galleys, he was told, had sailed to the Sea of Guinea; in that sea one was stranded, but the other passed on to a place on the coast of Aethiopia (here meaning Black Africa) — Mena or Amenuan, near the Gihon (here probably meaning the Senegal River) where the Genoese were seized and held in close captivity.
Sources.
The principal documentary source is the Genoese annals of Jacopo Doria, presented to the city of Genoa in 1294. Under the entry of the year 1291, Doria writes the following: 
Additional documents identify the other brother as "Vadino", that Tedesio Doria (Jacopo's nephew) did not embark, that the supplies were for "ten years", that the names of the vessels were "Sanctus Antonius" and "Alegranzia", and that the ship made a brief stop at Majorca before proceeding.
Geography.
Jean Gimpel suggests that the two Franciscan friars who accompanied the Vivaldi brothers may have read the "Opus Majus" written by their fellow Franciscan, Roger Bacon, in which Bacon suggested that the distance separating Spain and India was not great, a theory that was later repeated by Pierre d'Ailly and tested by Christopher Columbus.
It is uncertain how far the Vivaldi brothers reached. The Vivaldi brothers may have seen or landed on the Canary Islands. "Gozora" is a name found in some Medieval charts for Cape Non, which lies before the Canary Islands (e.g. "Caput Finis Gozole" in the maps of Giovanni da Carignano (early 1300s) and the Pizzigani brothers (1367)). The name of the ship "Alegranzia" may be the source for the Canary Island of Alegranza, and has led to the supposition that the brothers landed there (or that at least one of the ships capsized there).
An allusion to the Vivaldi galleys is given in the "Libro del Conoscimiento", a semi-fantastical travelogue written by an anonymous Spanish friar in c.1350-1385. There are two passages relating to the Vivaldi brothers. In the first, the narrator, traveling in what seems like the Guinea region (sub-Saharan Africa) reaches the city of "Graçiona", capital of the black African empire of "Abdeselib", which is allied to Prester John. "They told me in this city of Graciona that the Genoese who escaped the galley that was wrecked at Amenuan were brought (betrayed?) here, but it was never known what became of the other galley which escaped.". When the traveling friar moves on to the neighboring city of "Magdasor", he came across a Genoese man named "Sor Leone" who was in this city "searching for his father who had left in two galleys, as I have already explained, and they gave him every honor, but when this Sor Leone wanted to traverse to the empire of Graciona to search for his father, the emperor of Magdasor did not allow it, because way was doubtful and the path was dangerous" As it happens, Sorleone is the real name of Ugolino's actual son.
The location of these kingdoms have been much speculated. The references to Prester John and "Magdasor" (which sounds much like Mogadishu in Somalia) has led assume that it says the other galley circumnavigated Africa but was intercepted around the Horn of Africa. But the narrator's geographical references (e.g. to the Senegal-Niger River, the gold trade, the Mali Empire, even the Gulf of Guinea, suggests Abdelsalib and Magdasor are in non-Muslim sub-Saharan west Africa. The localization of "Amenuan", the place where the first galley capsized, is suggestive of Senegambia region. If there is a grain of truth in any of this, it would not stretch credulity to imagine that the Vivaldis got as far as Senegal, and that their adventures ended there.
A century later, in late 1455, Antoniotto Usodimare, a Genoese navigator in the service of Prince Henry the Navigator, claims rather improbably in a letter that while traveling up the Gambia River in West Africa, he came across a man who spoke the Genoese dialect and claimed to be the last descendant of the survivors of the Vivaldi expedition. (Usodimare's travelling companion, Alvise Cadamosto, mentions no such meeting in his memoirs.) Usodimare gives more details of the Vivaldi expedition in another document in the Genoese archives:
"Gion" is the name of Biblical Gihon river that stems from the Garden of Eden and flows through Ethiopia. In this instance, it may be a reference to the Senegal River. Usodimare's narration seems to be a mere repetition of the tale told in the "Libro del Conoscimiento".
The historian José de Viera y Clavijo writes that Father Agustín Justiniani, in the "Anales de Génova", includes the information that two Franciscans also joined the Vivaldi expedition. Viera y Clavijo also mentions the fact that Petrarch states that it was a local tradition that the Vivaldis did indeed reach the Canary Islands. Neither Justiniani nor Petrarch knew of the expedition's fate. Papiro Masson in his "Anales" writes that the brothers were the first modern discoverers of the Canary Islands.
The Vivaldi brothers subsequently became the subjects of legends that featured them circumnavigating Africa before being captured by the mythical Christian king Prester John. The Vivaldis' voyage may have inspired Dante’s Canto 26 of the "Inferno" about Ulysses’ last voyage, which ends in failure in the Southern Hemisphere. According to Henry F. Cary, Ulysses' fate was inspired "...partly from the fate which there was reason to suppose had befallen some adventurous explorers of the Atlantic ocean."