Just like the Stone and Bronze Ages, the Iron Age is named after the new technology of the time, in this case, iron!
Insert: Celtic Iron age mirror:
This Celtic (Iron Age) mirror was found by a metal detectorist in present day Portesham, Dorset
Just like the Bronze Age, as people moved and traded across Europe and Britain, the knowledge of how to work iron slowly spread from community to community. And just like the transition between Stone Age technology and Bronze Age technology, the transition between Bronze Age technology and Iron Age technology happened gradually.
In Britain, we date the start of the Iron Age to around 800BCE, and the end to 43CE, when the Romans invaded Britain.
So, why was iron favored more than bronze? Iron is a better metal than bronze because it is harder and tougher, meaning that iron tools and weapons were much sturdier. Also, iron ore is more widely distributed across Britain, making it more easily accessible to find than copper and tin, which are both needed to make bronze.
Besides the new iron technology, what else has changed in the Iron Age? Well, communities have grown and developed, and people have started to build fortifications around their settlements. We call these hillforts.