The story of King Mandhātā. It was told to a backsliding monk who, while travelling in Sāvatthi for alms, saw an attractively dressed woman and fell in love with her. This was reported to the Buddha, who told him this story to show that lust could never be satisfied. At the end of the discourse the monk, with many others, became a sotāpanna.
DhA.iii.240 gives a different occasion for the story; but that, too, refers to a discontented monk. J.ii.310ff.