or Ch'ang-an
Ancient capital of China during the Han , Sui , and Tang dynasties, near present-day Xi'an .
From the mid-4th century it was a centre of Buddhist studies. Wendi , first emperor of the Sui, expanded Chang'an: its outer walls were 6 mi (9.7 km) by 5 mi (8.2 km), with 14 avenues running north-south and 11 running east-west. The centre of the northern boundary was the site of the imperial palace; in front of it was an administrative compound 3 mi (4.5 km) square. Until the proscription of foreign religions in the 840s, Chang'an contained numerous Buddhist temples, along with Nestorian, Manichaean, and Zoroastrian churches and many Daoist monasteries. It was reduced to ruins in the 880s by the rebel Huang Zhao, and future dynasties established their capitals elsewhere.