Age of Discovery

===Early geographical knowledge and maps===
[[File:Adler von Lübeck. Model ship 05.jpg|left|thumb|upright|[[Pintle]]-and-[[gudgeon]] stern-post rudder of the [[Hanseatic league]] flagship ''[[Adler von Lübeck]]'' (1567–1581).]]The ''[[Periplus of the Erythraean Sea]]'', a document dating from 40 to 60 AD, describes a newly discovered route through the [[Red Sea]] to [[India]], with descriptions of the markets in towns around Red Sea, [[Persian Gulf]] and the Indian Ocean, including along the eastern coast of Africa, which states "for beyond these places the unexplored ocean curves around toward the west, and running along by the regions to the south of Aethiopia and Libya and Africa, it mingles with the western sea (possible reference to the Atlantic Ocean)". European medieval knowledge about Asia beyond the reach of the [[Byzantine Empire]] was sourced in partial reports, often obscured by legends,<ref>[[#Arnold 2002|Arnold 2002]], p. xi.</ref> dating back from the time of the conquests of [[Alexander the Great]] and his successors.
Another source was the [[Radhanite|Radhanite Jewish trade networks]] of merchants established as go-betweens between Europe and the Muslim world during the time of the [[Crusader states]].

[[File:Ptolemy Cosmographia 1467 - world map.jpg|thumb|upright=1.35|[[Ptolemy's world map]] (2nd century) in a 15th-century reconstruction by [[Nicolaus Germanus]].]]
In 1154, the [[Geography in medieval Islam|Arab geographer]] [[Muhammad al-Idrisi]] created a description of the world and a [[world map]], the [[Tabula Rogeriana]], at the court of King [[Roger II of Sicily]],<ref name=houben>Houben, 2002, pp. 102–04.</ref><ref name=harley>Harley & Woodward, 1992, pp. 156–61.</ref> but still Africa was only partially known to either Christians, Genoese and Venetians, or the Arab seamen, and its southern extent unknown. There were reports of great African [[Sahara]], but the factual knowledge was limited for the Europeans to the Mediterranean coasts and little else since the Arab blockade of North Africa precluded exploration inland. Knowledge about the Atlantic African coast was fragmented and derived mainly from [[Early world maps|old]] Greek and Roman maps based on Carthaginian knowledge, including the time of [[Ancient Rome|Roman]] exploration of [[Mauritania]]. The [[Red Sea]] was barely known and only trade links with the [[Maritime republics]], the [[Republic of Venice]] especially, fostered collection of accurate maritime knowledge.<ref>[[#Abu-Lughod 1991|Abu-Lughod 1991]], p. 121.</ref>

Indian Ocean trade routes were sailed by Arab traders. Between 1405 and 1421, the [[Yongle Emperor]] of [[Ming dynasty|Ming China]] sponsored a series of long range [[Treasure voyages|tributary missions]] under the command of [[Zheng He]] (Cheng Ho).<ref name="auto">[[#Arnold 2002|Arnold 2002]], p. 7.</ref> The fleets visited [[Arabian Peninsula|Arabia]], [[East Africa]], [[India]], [[Maritime Southeast Asia]] and [[Thailand]]. But the journeys, reported by [[Ma Huan]], a [[Muslim]] voyager and translator, were halted abruptly after the emperor's death<ref name="Mancall 2006">[[#Mancall 2006|Mancall 2006]], p. 17.</ref> and were not followed up, as the Chinese [[Ming dynasty]] retreated in the ''[[haijin]]'', a policy of [[isolationism]], having limited maritime trade.

By 1400, a Latin translation of [[Ptolemy]]'s ''[[Geographia]]'' reached Italy coming from Constantinople. The rediscovery of Roman geographical knowledge was a revelation,<ref>[[#Arnold 2002|Arnold 2002]], p. 5.</ref> both for map-making and worldview,<ref>[[#Love 2006|Love 2006]], p. 130.</ref> although reinforcing the idea that the Indian Ocean was landlocked.