In the continent of TIRRA, I am setting the world notes in the Age of Swords. Why did I choose that era?
The ages each have meaning. TIRRA is lacking in iron, and therefore must make do with copper, zinc, nickel, and tin and so on. Swords made of bronze may look impressive, but they really just don’t hold up very well against an armored opponent. Unless you are very good at only attacking soft spots on your opponents armor, your sword will dull and/or break eventually.
Which is why swords are reserved for unarmored opponents, and are becoming a symbol across large swaths of TIRRA as symbols of repression.
This then is the age when governments are sometimes finding advantage in slavery, and in forcibly keeping populations at fearful and oppressed. Who will win – the swords or the peasants?