In Malory’s Le Morte Darthur, Sir Lanceor, the son of the King of Ireland, rode out after Sir Balin, Lanceor’s lady Colombe came after him.
And when she aspied that Lanceor was slain, she made sorrow out of measure, and said, O Balin, two bodies thou hast slain and one heart, and two hearts in one body, and two souls thou hast lost. And therewith she took the sword from her love that lay dead, and fell in a swoon. And when she arose she made great dole out of measure, the which sorrow grieved Balin passingly sore, and he went unto her for to have taken the sword out of her hand, but she held it so fast he might not take it out of her hand unless he should have hurt her, and suddenly she set the pommel to the ground, and drove herself through the body.
King Mark of Cornwall arrived, buried Launeor and Colombe, and erected a tomb on which he wrote their story and the circumstances of their deaths.
The Post-Vulgate calls the same woman Lione and her paramour Launceor (Lancelor of Ireland).
Source
Le Morte Darthur | Sir Thomas Malory, 1469-1470