How we cite our quotes: (Chapter.Page)
Quote #1
Before they left Ireland, Yseut's mother prepared a love potion which she entrusted to Brangain, Yseut's maid, and instructed her to give it to Yseut and her husband to drink on the wedding night. (1.44)
Yseut's mother wants to make sure that her daughter feels love for her new husband. It seems like she has a more "modern" view of marriage—one in which it is ideally a love connection between the husband and wife, rather than just an exchange of property. Boy, do things turn out differently.
Quote #2
By mistake, Brangain brought the love potion and handed it to Tristan, who drank and passed it to Yseut. Both thought it was good wine; neither knew that it held for them a lifetime of suffering and hardship and that it was to cause their destruction and their death. After some hesitation Tristan and Yseut confessed their love, and it was soon consummated. (1.44-45)
Yup, that's right: the greatest and most famous love affair in all of medieval literature is a tragic mistake. Tristan and Yseut aren't initially attracted to one another because they're soul mates but because they're under the influence of magic. (Or, wait, is that the same thing? Metaphorically speaking?) Although this fact might seem to cheapen their love just a little bit, the love potion may symbolize the way all love supposedly makes the lovers powerless to resist it.
Quote #3
'Tristan, I am sure the king does not realize that I have loved you for his sake; I loved you because we were related. I used to think that my mother dearly loved my father's family, and she said that a wife who does not do so does not love her lord: I am certain this was right. I have loved you because of him and by doing this I have lost all his good will.' (2.49)
Yseut knows that Mark is listening to her at this point, so she plays the role of a dutiful wife who loves her in-laws for her husband's sake. The kind of love that Yseut feigns here—platonic filial love—is the same category of love she will claim she actually feels for Tristan after the potion wears off. But her deception here makes that later claim of filial love suspect by association.