Short answers, pulled from the story.
The oldest gold treasure in the world was discovered at the Varna Necropolis in Bulgaria. This site is located approximately 4 kilometers from the modern city of Varna and dates from the 5th millennium BCE.
The Hittites invented the method to extract iron from its ore around the 12th century BCE. This technique required temperatures and processes that were not mastered until that time, marking the beginning of the Iron Age.
A German scholar named Georg Agricola published the book De re metallica in the 16th century. His work described the complex processes of mining and metallurgy, earning him the title of the father of metallurgy.
Henry Clifton Sorby invented the technique of metallography to study the microscopic and macroscopic structure of metals. This method allows metallurgists to examine the composition and mechanical properties of an alloy by grinding and polishing it to a mirror finish.
The Wootz process was developed in the Indian subcontinent as early as 300 BCE. This ancient Indian technique produced ultra-high carbon steel with natural inclusions of Vanadium that exhibited superplasticity and high impact hardness.
Annealing softens the metal by heating it and then allowing it to cool very slowly. Quenching cools the metal very quickly after heating, freezing the metal's molecules in the very hard martensite form.