How we research: sources first

Mysterious subjects attract rumours. Our rule is simple: sources first.

Our method

• We start from primary texts and well-documented studies.
• We note where each claim comes from.
• We separate evidence, tradition and speculation, and label each one.
• We update our books when better evidence appears.

Your part

If you find a mistake or know a better source, please tell us through the Feedback page. Corrections make the books stronger.