At the beginning of his romance, Gottfried von Strassburg tells the story of Riwalin and Blanscheflur, Tristan's parents. Riwalin, ruler over Parmenie and vassal of Morgan, undertakes an educational journey to the court of King Marke in Cornwall, where he falls in love with Marke's sister Blanscheflur. After he is severely wounded, Blanscheflur goes to him in disguise, the two consummate their love, and Blanscheflur conceives Tristan. Subsequently Riwalin secretly returns with Blanscheflur to Parmenie, where the two marry at the altar. In the course of a campaign against his overlord Morgan, Riwalin is killed, and news of his fate leads to the premature birth of Tristan and to the death of his mother Blanscheflur. Already in Eilhart's Tristrant, which I believe is based on the same source as the romance of Thomas, there had been a short story about the parents of Tristan preceding the main story. For this reason one may assume that the story about the parents was part of the original Tristan story upon which all the later Tristan romances were more or less loosely based (see Buschinger 1995, 51). Thomas had already expanded this story about the parents, and it is clear that Gottfried von Strassburg — whose Tristan was based on Thomas's romance — and possibly even Thomas before him shaped the story of the parents in a manner that anticipates that of Tristan and Isolde (see Ruh 231). In this assessment of the relationship of the story about the parents to the main story about Tristan and Isolde, I will show how the earlier story took shape and was lengthened as many elements of the story about Tristan and Isolde were incorporated into it. I will focus on a few important points of correspondence between the story of Tristan's parents and the later story of Tristan and Isolde, particularly on the depiction of love (for detailed studies of the Riwalin-Blanscheflur story, see Nowé, Poag, and Okken), and in the comparison of the different versions of the Tristan story I will use the Tristrams saga of Friar Robert as representative of the missing text of Thomas.