I want to know the answer to the following question:
In what century was polygenism most widespread?
All the background I'm provided with is that "Polygenism was popular and most widespread in the 19th century, culminating in the founding of the Anthropological Society of London (1863) during the period of the American Civil War, in opposition to the Ethnological Society, which had abolitionist sympathies.". Is that enough to answer the question?
Answer: yes