A small number of alleged Hypogea, earthen structures carved into rocks that were used for burials, have been identified on the islands of Corvo, Santa Maria and Terceira by Portuguese archaeologist Nuno Ribeiro and speculations were published that they might date back 2000 years, alluding to a human presence on the island before the Portuguese. However, these kind of structures have always been used in the Azores to store cereals and suggestions by Ribeiro that they might be burial sites are unconfirmed. Detailed examination and dating to authenticate the validity of these speculations is lacking. So far, it is unclear whether these structures are natural or man-made and they predate the 15th-century Portuguese colonization of the Azores. Solid confirmation of a pre-Portuguese human presence in the archipelago has not yet been published.
The discovery and settlement of the Azores archipelago, much like the islands of Madeira, is one of the more controversial aspects of the Portuguese Age of Discovery. In addition to many theories, myths and stories written about the Azores there have been various Genoese and Catalan maps produced since 1351 that identified islands in the Atlantic. Some chroniclers note that sailors knew of the islands, and visited them during return voyages from the Canary Islands (about 1340–1345), during the reign of King Afonso IV. In "A History of the Azores" by Thomas Ashe written in 1813 the author identified a Fleming, Joshua Vander Berg of Bruges, who made land in the archipelago during a storm on his way to Lisbon. Ashe then claimed that the Portuguese explored the area and claimed it for Portugal shortly after. Other stories note the discovery of the first islands (São Miguel Island, Santa Maria Island and Terceira Island) were made by sailors in the service of Henry the Navigator, although there are few written documents to support the claims. Supporting the official history of the islands are latter day writings, based on oral tradition, that appeared in the first half of the 15th century. Legends and myths also developed during pre-official history to include myths about Prester John, the "Ilhas Afortunadas" (the Fortunate Isles), the "Ilhas Azuis" (the Blue Islands), the "Ilhas Cassiterides" (the islands of Tin and Silver) or "Ilhas de Sete Cidades" (the islands of the Seven Cities), all noting the knowledge of undiscovered lands in the middle of the Atlantic.
Officially, the first islands were "discovered" in the 15th century (in 1431) by Gonçalo Velho Cabral a Captain in the service of Infante D. Henrique, though credit is also given to the explorer Diogo de Silves (in 1427).
