1922, Shigeyoshi Obata, transl., Li Po, the Chinese Poet, page 180:
These passages refer, of course, to the rebellion of An Lu-shan. General Ku Shu defended the Han-ku Pass, which is an older name for Tun Kuan. By the twin imperial cities the poet very probably means Hsing-yang and Chang-an, unless he means the latter and city of Lo-yang.
On the whole we can state that if there is any local information about the finds of gold and silver vessels from T'ang, then Ch'ang-an — present Hsi-an — or Lo-yang with their neighbourhood is referred to.
The Tu’pa (Toba) removed their capital southward to Lo-yang at the end of the 5th century, and Sui rulers resided there at intervals during the 6th century. Lo-yang was a Buddhist centre during the 6th and 7th centuries. After the 10th century the city declined to a position as a local administrative and trade centre. Thus Lo-yang occupies an important historical niche in Chinese culture and, because of its many ruins, tombs and walls, was for centuries one of the historic tourist centres of China. It was called Honanfu until 1913.
Eventually, the ramshackle Chou government fell apart. In 771 BC the barbarian Jung tribes sacked the Chou capital at Hao, and forced the court to flee eastwards down the Yellow River to Lo-yang. Most of the king's vassals failed to support him in this crisis. This is the context for the famous story about the foolish emperor who called out his nobles with their troops for a joke, to amuse his concubine, so that when a real invasion occurred they no longer took any notice. Whatever the truth of this, the Chou ruler could no longer rely on his over-mighty subjects.
“Selected Glossary”, in The Cambridge Encyclopedia of China, Cambridge University Press, 1982, →ISBN, →LCCN, →OCLC, pages 476, 482: “The glossary includes a selection of names and terms from the text in the Wade-Giles transliteration, followed by Pinyin,[…]Lo-yang (Luoyang) 洛陽”