Later Yan

State · 387–409 CE · at its largest around 394 CE

Sixteen Kingdoms state founded by Murong Chui of the Xianbei after the collapse of Former Qin, later driven out of the central plains by Northern Wei.

On its lands while it lasted

• Ye (c. 337–576 CE): Capital of Later Zhao (337–351), Northern Qi (555–576).
• Lanzhou (c. 387 CE): Capital of Western Qin (387–431).
• Pingcheng District (c. 387 CE): Capital of Northern Wei (387–533).
• Zhangye (c. 397 CE): Capital of Northern Liang (397–439).

More on Wikipedia.