Composed in the middle of the 14th century, it is the longest of the indigenous riddarsögur and has no known foreign-language source. After a feast, Remundr, the son of the Christian king of Saxland, dreams of a strange country with three fantastic buildings. The third is a castle with a revolving chamber on top. In the dream, Remundr, weds a beautiful maiden, but awakens before he can consummate the relationship. When he awakes, the wedding ring is on his finger. The remainder of the tale chronicles his efforts to obtain her. His first obstacle is a giant named Eskupart, who wounds him in battle leaving the point of his sword lodged in his head, via a curse that can only be broken by Elina, the woman of the dream. Arriving in Africa, he must fend off the advances of a king's daughter and as a consequence is attacked by the king's men. His affliction worsens in India until anarchbishop sends Elina to remove the piece of iron from his head. When the Prince of Sicily arrives to woo her, Rumndr defeats him. With the help of a stone that renders him invisible, he is able to pay nightly visits to her. After returning home and fending off a pagan invasion of his country, he returns to India by way of Jerusalem with an army of 20,000 men, marries Elina, and returns to Saxland to be crowned.
“[T]he king of Denmark is given three stones by one of his own subjects, a man who has just returned from India, where he himself was given the stones by a local ruler. Although the Danish king admits he knows nothing at all of the stones’ value, he keeps them in case the giver should ask one day for reciprocation. As it turns out, a messenger from India does arrive at the king’s court with a request for something in return, to which the king replies: “I don’t know how the merit any recompense, for I do not see what can be done with them.” The Indian then demonstrates their virtues: One multiplies gold, the second protects against wounds in battle, and the third transports the users to India-- whereupon the Indian vanishes.”
Barnes (p. 223) on the link between the saga and the Prester John legend:
“Although the legend itself has not been considered as a possible influence on the narrative action, by arriving directly from Furthest India to defend Germany and France against invasion from Tartary, Rémundr, as the heir and surrogate of Prester John, embodies the crusader fantasy of the Christian ruler of the East who delivers European Christendom from heathen onslaught. The historical memory of the Mongol invasion and the legend of Prester John ultimately combine in Rémundar saga keisarasonar to rewrite history in one or a combination of two scenarios: first, Rémundr succeeds where Henry of Silesia and Béla of Hungary failed, and second, he enacts the German crusade against the Mongols that never happened.”