What was the situation of calligraphy in the Sui and Tang Dynasties?

In the Sui Dynasty, there was a fusion of calligraphy styles from the north and the south in the art of calligraphy. "Longzang Temple Stele" and "Dong Meiren's Epitaph" are its representatives. The main literati and calligraphers are monk Zhiyong, a descendant of Wang Xizhi. In terms of calligraphy theory, "Longzang Temple Stele" began to attach importance to the summary of the technical rules of writing, and the first article dedicated to "Dharma" appeared - "Ode to the Heart" by monk Zhiguo.