How do you calculate the year of swords or crowns? Husni

The same as you calculate the age of any object, by comparing it to other examples that you know the date of. So, if you found a sword, you would first look to see what it was made of: if it was made of Bronze then it might be Bronze Age, if it was of iron then it might be Iron Age (or later). Then you would look to see if any swords like that had been found with a burial – as if they had then the skeleton might have been dated using radiocarbon dating. So the date for the skeleton would give you a date for the sword that was found with it. So it’s a mixture of comparing and using science.