Complex sentence: Sailing from Hong Kong in July, the capture of the Taku Forts on 21 August 1860 had opened up the river route to Peking, the Chinese authorities at the fort had capitulated all 22 forts along the river as far as Tientsin, including that town.
Split into simpler sentences: Sailing from Hong Kong in July, the capture of the Taku Forts on 21 August 1860 had opened up the river route to Peking. The Chinese authorities at the fort had capitulated all 22 forts along the river as far as Tientsin, including that town.