During the Sui and Tang dynasties, the economy of China prospered, exchanges with the outside world were frequent, and glorious scientific and cultural achievements appeared. Calligraphy, painting and sculpture flourished in the Tang Dynasty. In particular, Tang Dynasty poetry is regarded as the acme of this genre, represented by the poets Li Bai and Du Fu. In the field of prose literature, Han Yu and Liu Zongyuan were outstanding. Tang was one of the richest and most powerful countries in the world at that time.