Where was the capital of Tang Dynasty and Xuanzong period?

The capital of the Tang Dynasty was Chang 'an (now Xi 'an, Shaanxi).

Li Longji (September 8, 685-May 3, 762) was in office from 7 12 to 756. The longest-serving emperor in the Tang Dynasty, Tang Ruizong's third son Li Dan, and his mother Dou Defai. Because posthumous title is "Great Sage, Daming and Filial Piety", the temple name "Xuanzong" is also called Emperor Taizong. In the Qing Dynasty, Emperor Kangxi's name "Michelle Ye" was taboo. He was often referred to as Emperor Tang, and another one was honored as "Emperor Kaiyuan".

Li Longji was born in August of the first year of Hanggong (685) in Luoyang, the eastern capital. He is wise and decisive, versatile, knows rhythm, is good at calligraphy, and is handsome. During the Yongchang period (689), Li Dan's eldest brother was succeeded as Emperor Li Hong of Xiaozong, first named King Linzi, and later changed King Chu to Luzhou's special bus driver.