His faithful steward Kurvenal, hoping yet to save him, sailed for Cornwall to bring the other Iseult to the rescue; and as he left he promised his master to change the black sails of the vessel for white in case his quest were successful.
Tristan now watched impatiently for the returning sail, but just as it came into view he breathed his last.

Some ill-advised writers have ventured to state that Iseult of Brittany, whose jealousy had been aroused, was guilty of Tristan's death by falsely averring, in answer to his feverish inquiry, that the long-expected vessel was wafted along by black sails; but, according to other authorities, she remained gentle and lovable to the end.
[Sidenote: Miracle of the plants.] Iseult of Cornwall, speeding to the rescue of her lover, whom nothing could make her forget, and finding him dead, breathed her last upon his corpse.

Both bodies were then carried to Cornwall, where they were interred in separate graves by order of King Mark.

But from the tomb of the dead minstrel there soon sprang a creeper, which, finding its way along the walls, descended into Iseult's grave.
Thrice cut down by Mark's orders, the plant persisted in growing, thus emphasizing by a miracle the passionate love which made this couple proverbial in the middle ages.

There are in subsequent literature many parallels of the miracle of the plant which sprang from Tristan's tomb, as is seen by the Ballad of Lord Thomas and Fair Annet, and of Lord Lovel, where, as in later versions of the Tristan legend, a rose and a vine grew out of the respective graves and twined tenderly around each other.
"And out of her breast there grew a red rose, And out of his breast a brier." _Ballad of Lord Lovel_..