From
元好问《
摸鱼儿·
雁丘词》(Yuan Haowen, 'Mo Yu'er: Song of the Wild Goose Mound,' Jin dynasty, c. 1205 CE):
问世间,
情是何物,
直教生死相许?(I ask the world: what kind of thing is love, that it makes life and death be pledged to each other?) Yuan wrote it at 16, after a hunter told him a wild goose had killed itself seeing its mate shot down. Famously rephrased as
问世间情为何物 in the wuxia novel 《
神雕侠侣》(The Return of the Condor Heroes) by Jin Yong.