Prester John in the context of "Orient"

Ethiopian historiography includes the ancient, medieval, early modern, and modern disciplines of recording the history of Ethiopia, including both native and foreign sources. The roots of Ethiopian historical writing can be traced back to the ancient Kingdom of Aksum (c. AD 100 – c. 940). These early texts were written in either the Ethiopian Ge'ez script or the Greek alphabet, and included a variety of mediums such as manuscripts and epigraphic inscriptions on monumental stelae and obelisks documenting contemporary events. The writing of history became an established genre in Ethiopian literature during the early Solomonic dynasty (1270–1974). In this period, written histories were usually in the form of royal biographies and dynastic chronicles, supplemented by hagiographic literature and universal histories in the form of annals. Christian mythology became a linchpin of medieval Ethiopian historiography due to works such as the Orthodox Kebra Nagast. This reinforced the genealogical traditions of Ethiopia's Solomonic dynasty rulers, which asserted that they were descendants of Solomon, the legendary King of Israel.

Ethiopian historiographic literature has been traditionally dominated by Christian theology and the chronology of the Bible. There was also considerable influence from Muslim, pagan and foreign elements from within the Horn of Africa and beyond. Diplomatic ties with Christendom were established in the Roman era under Ethiopia's first Christian king, Ezana of Axum, in the 4th century AD, and were renewed in the Late Middle Ages with embassies traveling to and from medieval Europe. Building on the legacy of ancient Greek and Roman historical writings about Ethiopia, medieval European chroniclers made attempts to describe Ethiopia, its people, and religious faith in connection to the mythical Prester John, who was viewed as a potential ally against Islamic powers. Ethiopian history and its peoples were also mentioned in works of medieval Islamic historiography and even Chinese encyclopedias, travel literature, and official histories.

Prince Henry of Portugal, Duke of Viseu (Portuguese: Infante Dom Henrique; 4 March 1394 – 13 November 1460), better known as Prince Henry the Navigator (Portuguese: Infante Dom Henrique, o Navegador), was a Portuguese prince and a central figure in the early days of the Portuguese Empire and in the 15th-century European maritime exploration. Through his administrative direction, he is regarded as the main initiator of what would be known as the Age of Discovery. Henry was the fourth child of King John I of Portugal, who founded the House of Aviz.

After procuring the new caravel ship, Henry was responsible for the early development of Portuguese exploration and maritime trade with other continents through the systematic exploration of Western Africa, the islands of the Atlantic Ocean, and the search for new routes. He encouraged his father to conquer Ceuta (1415), the Muslim port on the North African coast across the Straits of Gibraltar from the Iberian Peninsula. He learned of the opportunity offered by the Saharan trade routes that terminated there, and became fascinated with Africa in general; he was most intrigued by the Christian legend of Prester John and the expansion of Portuguese trade. He is regarded as the patron of Portuguese exploration. He is also considered to be one of the most responsible for developing the slave trade in Western Europe. The prince died on 13 November 1460 in Vila do Bispo, Algarve.

The Keraites (also Kerait, Kereit, Khereid, Kazakh: керейт; Kyrgyz: керей; Mongolian: ᠬᠡᠷᠢᠶᠡᠳ, Хэрэйд; Nogai: Кереит; Uzbek: Kerait; Chinese: 克烈, Persian: کرایت) were one of the five dominant Turco-Mongol tribal confederations (khanates) in the Altai-Sayan region during the 12th century. They had converted to the Church of the East (Nestorianism) in the early 11th century and are one of the possible sources of the European Prester John legend.

Their original territory was expansive, corresponding to much of what is now Mongolia. Vasily Bartold (1913) located them along the upper Onon and Kherlen rivers and along the Tuul river. They were defeated by Genghis Khan in 1203 and became influential in the rise of the Mongol Empire, and were gradually absorbed into the succeeding Mongol khanates during the 13th century.