In this Thursday, December 4, 2025 lecture to his Beijing high school students, Professor Jiang explains how the Catholic Church became the ultimate empire. Notes and References: 1. Albigensian Crusade: https://en.wikipedia.org/wiki/Albigensian_Crusade 2. Sasanian Conquest of Jerusalem: https://en.wikipedia.org/wiki/Sasanian_conquest_of_Jerusalem 3. The Quran