Complex sentence: In Sukhothai Kingdom era, "Mueang" Kosamphi was a satellite city of the frontier city Mueang Chakangrao (Kamphaeng Phet), at same level as "Mueang" Nakhon Chum, Trai Trueng, Phan and Phangkha.
Split into simpler sentences: In Sukhothai Kingdom era, "Mueang" Kosamphi was a satellite city of the frontier city, Mueang Chakangrao (Kamphaeng Phet). It was in the same city grade as Mueang Nakhon Chum, Trai Trueng, Phan and Phangkha.