Who is the author of the ancient poem Xiaocao?

[Ancient poem "Grass"]

Bai Juyi's Farewell to Ancient Grass is also called Grass.

The endless grass on the plain comes and goes with each season.

Wildfire never completely devoured them, and they grew taller again in the spring breeze.

Sweet they pressed on the old highway and reached the crumbling gate.

Oh, my friend's prince, you left again, and I heard them sigh behind you.