The upper reaches of the White Nile remained largely unknown to the ancient Greeks and Romans because they were unable to penetrate the Sudd wetlands in South Sudan. The river’s source was not found by any of the expeditions. According to Agatharchides, a military expedition from Ptolemy II Philadelphus had traveled far enough along the Blue Nile to determine that the summer floods in the Ethiopian Highlands were brought on by heavy seasonal rainstorms. However, it is known that no European from antiquity ever reached Lake Tana. The Tabula Rogeriana portrayed the source as three lakes in 1154.
Europeans started to find out about the beginnings of the Nile in the fourteenth century when the Pope sent priests as messengers to Mongolia who passed India, the Center East and Africa, and depicted being recounted the wellspring of the Nile in Abyssinia (Ethiopia) Later in the fifteenth and sixteenth hundreds of years, explorers to Ethiopia visited Lake Tana and the wellspring of the Blue Nile in the mountains south of the lake.
Supposed Venetian traveler Paolo Trevisani, who lived in Ethiopia between the years 1452 and 1483, kept a journal about his journey to the Nile’s source, but the journal has since vanished. Modern authors give the credit to the Jesuit Pedro Páez, despite James Bruce’s claim that he was the first European to visit the headwaters. Ethiopia is detailed and long-winded in Páez’s account of its source. Even though it was mentioned in works by Páez’s contemporaries Baltazar Téllez, Athanasius Kircher, and Johann Michael Vansleb, it was only fully published in the early 20th century.