Emperor Gaozong of Tang
The "Daci'ensi sanzang fashizhuan" 大慈恩寺三藏法師傳 "Biography of the Tripitaka Dharma Master of the Temple of Great Compassionate Blessings" is a biography of Xuanzang (see the "Xiyouji" below) written by his disciple Kuiji (or Ci'en, the namesake temple in Luoyang, see Emperor Gaozong of Tang). This record of the Consciousness-Only (Yogacara) Buddhism, has a memorial dated 657 CE that parallels "yima" "idea-/will-horse" with "qingyuan" 情猿 "emotion-/feeling-monkey": "Now if you wish to entrust your thoughts to the Chan sect, you must make your mind as pure as still water, control your emotion-monkey's indolence and fidgeting, and restrain your idea-horse's haste and galloping."