As for poetry, what does this sentence mean? As for Han's retreat, as for Wu Daozi's painting, as for Yan's writing, the change of ancient and modern times?

As for poetry, as for Han's retreat, as for Wu Daozi's painting, as for Yan, the changes of ancient and modern times are all in the world.

Poetry went to Du Fu, prose to Han Yu, calligraphy and painting to Wu Daozi, and calligraphy to Yan Zhenqing. It can be said that artistic flexibility has been exhausted through the ages.