What shared knowledge should audiences of My Fair Lady have to better appreciate the deeper meaning of the musical?

Conquistadors were soldiers and explorers of the Spanish Empire or the Portuguese Empire in a general sense. During the Age of Discovery, conquistadors sailed beyond Europe to the Americas, Oceania, Africa and Asia, conquering territory and opening trade routes. They colonized much of the world for Spain and Portugal in the 16th, 17th and 18th centuries. During this time period there was many diseases that were brought from Spain and Portugal to the Americas. The Indian's immunity was weak due to the fact that they had never been exposed to the diseases that were spreading that came from Spain and Portugal.