I found a Grimm story I hadn't read before today.
A poor young man left his home with his father's blessing, as his father could no longer support him, and went to war for a King. He was brave in battle, rallying the troops when all seemed lost, and defeating the enemy. When the King heard that he owed the victory to him alone, he raised him above all the others, gave him great treasures, and made him the first in the kingdom.
The King had a daughter who was very beautiful, but she was also very strange. She had made a vow to take no one as her husband who did not promise to let himself be buried alive with her if she died first. On her side she would do the same, and if he died first, would go down to the grave with him. This strange oath had up to this time frightened away all suitors, but the young...