Tannhäuser, a knight of medieval legend, who wins the affection of a lady, but leaves her to worship in the cave-palace of Venus, on learning which the lady plunges a dagger into her heart and dies; smitten with remorse he visits her grave, weeps over it, and hastens to Rome to confess his sin to Pope Urban; the Pope refuses absolution, and protests it is no more possible for him to receive pardon than for the dry wand in his hand to bud again and blossom; in his despair he flees from Rome, but is met by Venus, who lures him back to her cave, there to remain till the day of judgment; meanwhile the wand he left at Rome begins to put forth green leaves, and Urban, alarmed, sends off messengers in quest of the unhappy knight, but they fail to find him.