What is the time division between ancient poetry and modern poetry?

The time limit between modern poetry and ancient poetry is the Tang Dynasty. Take (and include) the ancient style of the Tang Dynasty and the poems before the new Yuefu as ancient styles, and the following metrical poems and quatrains are modern poems.

Metrics of Modern Poetry: On the basis of predecessors, court poets in the early Tang Dynasty studied phonology and antithesis, and leveled the metrical poems. Classical poetry is not flat, only rough rhyme. After the appearance of metrical poetry, it quickly led the poetry circle, corresponding to the ancient poetry before the Tang Dynasty. At that time, the poet gave this new poetic style a name: "Modern Poetry". Of course, people in the Tang Dynasty called their inventions modern style.

The difference between ancient poetry and modern poetry

(1) The number of words and sentences is not limited, and it can be four, five, seven words or miscellaneous words; It can be at least two sentences, such as Fu Xuan's Miscellaneous Words; Up to more than 300 sentences, such as "Ancient Poetry as Jiao Zhongqing's Wife" ***357 sentences.

(2) Rhyme is not strict. It can be changed, passed, flat or rhymed.

(3) Don't talk about leveling.

(4) Don't talk about antithesis.