Why was Tengwangge praised as "fountain pen" by the ancients?

Wang Tengting is known as "the first floor of Xijiang River". Located in Hebei Avenue, Nanchang Prefecture, Jiangxi Province, at the intersection of Ganjiang River and Fuhe Old Road. Wang Tengting was built in 653, named after Li Yuanying, the younger brother of Emperor Taizong of Tang Dynasty. Because of the poem "The sunset is lonely in Qi Fei, the autumn water is * * * and the sky is one color" written by Wang Bo, a poet in the early Tang Dynasty, it has been passed down to later generations. Tengwangge was praised by the ancients as a fountain pen, which occupied a sacred position in the eyes of the world and was highly valued by successive dynasties. Tengwangge is also a place for storing ancient books and history books. In a sense, it is the ancient library of China.