Steel, an alloy of iron and carbon whose strength, hardness, and flexibility can be modified through composition and processing, has been one of humanity’s most transformative materials. From early bloomery production in the ancient Near East (circa 1200 BCE) to advanced industrial and alloy steels of the 19th and early 20th centuries, civilizations developed increasingly sophisticated methods of smelting, refining, forging, and alloying to create materials with new properties and applications.

These metallurgical breakthroughs influenced nearly every aspect of human history. Superior steels improved agricultural productivity, enabled more durable tools and weapons, supported imperial expansion and long-distance trade, powered the Industrial Revolution (circa 1760 to 1900), and transformed infrastructure, transportation, medicine, and engineering.