Note - Whilst some phrases, like "The Iron Age" are in common usage, there does not appear to be precise definition for the time period encompassed by "The Iron Age." The figures indicated can only be regarded as a rough indication accurate to within a few thousand years! The problems get even worse as you go back in time and what is a few billion years when estimating the end of the first Ice Ace.
 
In England you will often see time periods named after the reigning monarch (e.g. Victorian named after Queen Victoria 1837-1901.) This can be further complicated by phrases like the "Tudor Period" names after the reigning "House." (In thie context, a house is a set of consecutive monarchs from the same family.) If you investigate early English history, please remember that England formed from the gradual merger of smaller nations (including Wessex, Nothumbria and Mercia.)