Why was Buddhism first accepted and ended by the tang rulers?

Buddhism was initially accepted by Tang rulers because it aligned with their goals of promoting cultural unity and providing spiritual support in a rapidly expanding empire. The religion's teachings on compassion and enlightenment appealed to the ruling elite, who sought to legitimize their authority. However, by the late Tang period, the state turned against Buddhism due to its growing influence, perceived wealth, and the belief that it threatened Confucian values and social order, leading to the suppression and decline of the religion. The infamous Huichang persecution in the 840s marked a significant turning point in this rejection.