One summer evening in 335 BCE, Alexander the Great was resting by the Danube River when a band of strangers approached his camp. Alexander had never seen anything like these tall, fierce-looking warriors with huge golden neck rings and colorful cloaks. They were Keltoi or Celts— a collection of independent tribes spread across Europe. Philip Freeman details the rise and fall of the ancient Celts. Lesson by Philip Freeman, directed by Paper Panther.