Feilong (; lit. "flying dragon") is a legendary creature that flies among clouds in Chinese mythology. Feilong is a proper name, and is often used as a title for other ideas and objects. The Chinese dragon name feilong combines fei or "fly; flying; hover; flutter" and long or "dragon". This loanword 飛龍 is pronounced as Japanese hiryū (飛竜), Korean biryong (비룡), and Vietnamese philong. The inverted Longfei 龍飛 was an era name (396–399 CE) during the Later Liang Dynasty. The (121 CE) Shuowen Jiezi, the first Chinese character dictionary, uses feilong to define da (written with 2 龍 dragons) "flying dragon; appearance of a dragon in flight". Chinese classic texts frequently mention feilong 飛龍 "flying dragons". The examples below are roughly arranged in chronological order, although some heterogeneous texts are of uncertain dates. The (5th–3rd centuries BCE) Yijing "Book of Changes" first uses feilong to symbolize a daren 大人 "great person; accomplished person". Qian 乾 "The Creative", the first hexagram, says, "Nine in the fifth place means: Flying dragons in the heavens. It furthers one to see the great man." The "Commentary on the Decision" (彖傳), explains, "Because the holy man is clear as to the end and the beginning, as to the way in which each of the six stages completes itself in its own time, he mounts on them toward heaven as though on six dragons." And the "Commentary on the Images" (象傳), says, "'Flying dragon in the heavens.' This shows the great man at work." Many later texts, such as the Zuozhuan, Shiji, and Hanshu histories, quote this "Flying dragons in the heavens" from the Yijing. The (3rd century BCE) Hanfeizi (難勢,) quotes Shen Dao contrasting feilong 飛龍 with tengshe 螣蛇 "ascending/floating snake" to explain the Legalist concept of shi 勢 "political power; strategic advantage". Shen Tzu said: "The flying dragon mounts the clouds and the t'eng snake wanders in the mists. But when the clouds dissipate and the mists clear, the dragon and the snake become the same as the earthworm and the large-winged black ant because they have lost that on which they ride.