Complex sentence: However, the late Empress's mother (one of the granddaughters of the late Jiaqing Emperor) and sisters were escorted by force to the Temple of Heaven, and were there gang-raped by several dozens of foreign soldiers.
Split into simpler sentences: However, the late Empress's mother (one of the granddaughters of the late Jiaqing Emperor) and sisters were escorted by force to the Temple of Heaven. Subsequently, they were gang-raped by several dozens of foreign soldiers.