The Liao State was founded earlier and longer, in fact, it has a much longer history than the Northern Song Dynasty, but its fame is far behind that of the Northern Song Dynasty. The Liao state of Yelü Abaoji was established in 916 AD, after 9 emperors, and in 209 the state was established. The Northern Song Dynasty was founded in 906 and experienced 9 emperors, only 167 years.
Speaking of the capital of the Liao State, many people misunderstand the "Five Capitals System" and think that the Liao State has five capitals (Shangjing Linhuangfu - present-day Inner Mongolia Bahrain Left Banner, Zhongjing Dadingfu - present-day Inner Mongolia Chifeng, Tokyo LiaoyangFu - present-day Liaoning Liaoyang, Xijing Datongfu - present-day Datong, Shanxi, Nanjing Jingjinfu - present-day Beijing).
In fact, the meaning of "Jing" in the Liao State has nothing to do with the country. There was never only one capital of the Liao State, and the "capital" outside the capital was not even a companion. So where is the Liao State?
When Yelü Abaoji (Liao Taizu) founded the country in 916, the capital of the Liao state was only "Shangjing LinhuangFu". In 947, Yelü Deguang (Emperor Taizong of Liao) attacked the Later Jin Dynasty, changed the "Great Khitan State" to "Great Liao State", and ascended the throne at Fenjing (Kaifeng), which briefly served as the capital of the state for 4 months, and later "Shangjing LinhuangFu".
In 1007, during the regency of Empress Xiao, the Liao state moved its capital to "Zhongjing Dadingfu". Since then, Zhongjing Dadingfu has been the capital of the Liao state. When Jurchen attacked the Liao state, first destroyed Liaodong, then Liao Shangjing, and then attacked Zhongjing, where The Liao Tianzuo Emperor was located, and the Liao state was scattered.
Since the other "Capitals" are not the capitals of the country, nor are they the capitals of the country, why are they also called "Beijing"?
So many "capitals" are related to the administrative division of the Liao State. The Liao State implemented a three-level administrative system: dao, prefecture (prefecture), and county, the highest level is "dao", the second level is "prefecture (prefecture)", and further down is "county".
The entire Liao state is divided into 5 provinces, with jurisdiction over 6 provinces, 156 prefectures, and 309 counties. According to the jurisdiction area: Shangjing Province (Mongolian Plateau), Tokyo Province (most of the northeast), Nishikyo Province, Nakagyo Province, Nanjing Province. Each province has a prefecture under it as a seat of government. For example, the political center (seat of government) of Xijing Province is Datong Province, and is it not very verbose to think of "Saigyo Province"? The abbreviation is "Xijing Datong Province".
In other words, these "Daos" of the Liao State are equivalent to the current provinces, and the "Jing" of the Liao State is equivalent to the current provincial capital. The big vernacular is that there are 5 provinces in the Liao state, and as long as it is a provincial capital, it is called "Beijing". Later, the Jin Dynasty destroyed the Liao State and also inherited some of this name, but the Jin State and the Song Dynasty liked to call it "Road" instead of "Dao". For example, the "Zhongjing Road" of the Liao Kingdom became the "Zhongjing Road" of the JinGuo.