"It is cele who prist / the one who his seignor Cistercians". Did the Yvain have a client between Lancelot and Grail?

The moral problem which Chretien de Troyes formulates in this couplet of his Yvain, in order to resolve it, with his characteristic elegance, untragically and yet in conformity with the chivalric code of honour - this problem had, in the reality of the twelfth century, an astonishing parallel in the triangle formed by Sibylla of Anjou and her husbands William Clito and Thierry of Alsace, the former of whom was killed in a feud with the latter. On the other hand, Sibylla and Thierry were the parents (happy, as it seems) of Philip of Alsace, the patron of Chretien's following and last romance, the Story of the Grail. Philip, known as a friend of letters, would certainly not have accepted to patronize the Grail without having informed himself rather thoroughly about the Yvain - which implies that he must have recognized the parallels with his parents and that he fully approved their treatment. But is it really by pure chance that Chretien could present to him a work which in advance suited Philip's interests so perfectly? Is it not simpler to consider Philip as the anonymous patron of Yvain right from the outset? To explain his anonymity in those turbulent years, one simply has an embarrassment of choice.