釋氏稽古略 3.442

3.442

十月。帝以大梁舟車所會便於漕運。乃建東京於汴州。復以汴州為開封府。以東都（洛陽）為西京。以西都（長安）為晉昌軍節度。

In the tenth month, because Daliang was a hub of boats and carriages convenient for grain transport, the emperor established the Eastern Capital in Bianzhou, and redesignated Bianzhou as Kaifeng Prefecture. He made the Eastern Capital (Luoyang) the Western Capital, and made the Western Capital (Chang'an) the Jinchang Army Military Commission.