First called
忆仙姿.
苏轼 renamed it after the words
如梦，
如梦 'as in a dream, as in a dream' in the earliest poem to the tune, by the Later Tang emperor
李存勖. It has only 33 characters and is cited with its first line as the title:
李清照 wrote 《
如梦令·
常记溪亭日暮》, which ends
惊起一滩鸥鹭, and 《
如梦令·
昨夜雨疏风骤》, the source of
绿肥红瘦.
