Complex sentence: The death of a second Emperor who was seemingly in good health within the span of a month became a source of alarm and gossip throughout the empire, and has since become known as the infamous "Case of the Red Pills" (Zh: 红丸案).
Split into simpler sentences: The death of a second Emperor who was seemingly in good health within the span of a month became a source of alarm and gossip throughout the empire. It became known as the infamous "Case of the Red Pills" (Zh: 红丸案).