Complex sentence: Both the Qing Dynasty and the Joseon Dynasty used matchlock rifles as late as the 1850s and 1870s, during the Second Opium War and the United States expedition to Korea.
Split into simpler sentences: Both the Qing Dynasty and the Joseon Dynasty used matchlock rifles as late as the 1850s and 1870s. During the Second Opium War and the United States expedition to Korea.