Why was steel or iron used to make armour in the 17th century?

Steel and iron were used to make armor in the 17th century due to their strength, durability, and ability to withstand the impact of weapons used during that time, such as sWords and early firearms. These metals could be effectively shaped and tempered to create protective gear that offered better defense compared to earlier materials like leather or cloth. Additionally, advancements in Metallurgy during this period allowed for improved production techniques, resulting in lighter and more effective armor suited for both infantry and cavalry.