User blog comment:Cfp3157/Greek Peltast vs. Inca Bola Thrower/@comment-422690-20151117024446/@comment-17814994-20151117032006

Well I do agree that iron only became significant when materials for bronze started diminishing. But it wasn't just the only reason why it became more popular. Iron has been existing during the bronze age but the process it just wasn't that perfected yet. But by the time of the Persian Empire iron was already in its prime shape.

Yes they are brittle but they are more durable and won't losr sharpness or bent easily as bronze. They are sharper and they don't loose that sharpness as quickly as bronze. Try bashing a bronze and iron sword at each other and the former would ten to lose.