A poem is a new poem composed of ready-made poems, which is selected separately from ready-made poems and then skillfully combined. Sentence-set poetry requires complete content, brand-new theme, harmony with the rhythm of poetry and nature. The word "sojourning" comes from Chen Shidao's Poems on the Back Hill in Song Dynasty, but its creation has a long history. The earliest extant poems of set sentences are Fu Xian's Seven Classics Poems in the Western Jin Dynasty.