William C. Dix (1837–1898) was an English poet and hymnwriter whose verses shaped Victorian sacred music. Though he composed primarily text rather than melody, his words for "What Child Is This?" became inseparable from the tune "Greensleeves," creating one of the most recognizable wedding of words and music in the English-speaking choral tradition.
Dix wrote during a period of vigorous hymn composition and poetry, and his gift lay in crafting singable, theologically direct verse that worked equally well in formal liturgy and community singing. His collaboration with existing melodies produced lasting results that continue to anchor seasonal and devotional programs.