中國古代音樂文學的創作模式主要有“以樂從辭”“選辭配樂”“由樂定辭”三種。“以樂從辭”的創作機理是“聲依永，律和聲”，這與“由樂定辭”的創作機理正好相反，“由樂定辭”的創作機理乃是“永依聲”。“選辭配樂”的創作機理是選既成之辭配入既成之曲，既有對辭的“拼湊分割”，亦有對曲的“填實虚聲”。“元狩、元鼎”與“開元、天寶”是三種創作模式轉折的兩個關鍵的時間節點，伴隨創作模式之變更，辭樂關係也隨之發生一定的微妙變動。

Yi yue cong ci 以樂從辭 (lit., to compose the melody according to the lyrics), xuan ci pei yue 選辭配樂 (lit., to select an existing lyrics to match an existing melody), and you yue ding ci 由樂定辭 (lit., to write the lyrics according to the melody) are the three major creative modes of classical Chinese musical literature. Yi yue cong ci’s mechanism is sheng yi yong, lü he sheng 聲依永, 律和聲 (the sound relies on the singing, and pitch-pipes harmonize sound), while you yue ding ci’s mechanism is the opposite yong yi sheng 永依聲 (the singing relies on the sound). Xuan ci pei yue’s mechanism features two methods of (1) cutting and piecing the lyrics and (2) matching a bstract sounds with lyrics. The Yuanshou 元狩 and Yuanding 元鼎 eras of the Han dynasty (122-117 BCE) and the Kaiyuan 開元 and Tianbao 天寶 eras of the Tang dynasty (713-756 CE) are two critical times when the three creative modes of Chinese musical literature underwent changes that added subtle complications to the melody-lyrics relationship.