The Ulfberht swords (9th–11th century) featured high-carbon steel so advanced it shouldn't have existed in Europe at that time. The theory is this "specialized" metal was either sourced through ancient trade routes (India or the Middle East) …or there was a small group of local smiths had specialized, rare knowledge that wouldn’t be commonplace in Europe for another 500 years.
by OilInternational2566
1 Comment
https://en.wikipedia.org/wiki/Ulfberht_swords