Queen of Lyonesse.
The sister of King Mark of Cornwall was "a full meek lady, and well she loved her lord", King Meliodas of Liones. While she was pregnant with Tristram, Meliodas was waylaid on a hunt and imprisoned by an enchantress who loved him.
When Elizabeth ... missed her lord, and she was nigh out of her wit, and also a great with child as she was, she took a gentlewoman with her, and ran into the forest to seek her lord.
Here she gave birth to her son.
But she had taken such cold for the default of help that deep draughts of death took her ... Now let me see my little child, for whom I have had all this sorrow. And when she saw him she said thus: Ah, my little son, thou hast murdered thy mother, and therefore I suppose, thou that art a murderer so young, thou art full likely to be a manly man thine age.
With this wry humor, and charging her gentlemwoman to ask the king to name his son Tristram, "that is as much to say as a sorrowful birth", she gave up the ghost and died.
She is probably to be identified with Eliabel or Eliabella from Italian romance.