Humanism, secularism, pluralism: these were the spirit of the age in the exchange system known as the Mongol Empire. So Roxann Prazniak finds in Sudden Appearances: The Mongol Turn in Commerce, Belief, and Art. Prazniak’s starting place is art history, but her study of artistic exchange opens out into a wide view of the intellectual and cultural world under Mongol globalization in the 13th century.