From Su Shi's (
苏轼) Song-dynasty ci 《
水调歌头·
明月几时有》, written on Mid-Autumn 1076 missing his brother Su Zhe. Closing couplet:
但愿人长久,
千里共婵娟 — 'Only wish that we may live long, and together share this fair moon across a thousand miles.'
婵娟 (chánjuān) here poetically refers to the moon. Teresa Teng's (
邓丽君) 1983 song 《
但愿人长久》 cemented the phrase in the modern imagination.