Why dating has to be done under the ground
According to Engberg, it is necessary to do an actual excavation because it is very difficult to date a building simply by looking at its walls.
“But you can take samples from the oldest mortar and try to date the carbon particles in the mortar. However, this method has not yet been fully developed and is still far too uncertain,” says Engberg.
The researchers cannot use the knowledge gleaned from the castle in the 19th century as a basis for dating, either.
The explanation for this lies in the way the castle ruin was excavated back then.
When they started excavating the ruins in the late 19th century the approach was more one of tidying up than excavating: they simply dug away, collecting whatever they found, Engberg explains:
“In an archaeological context we arrive at a date on the basis of the objects we find, and all sorts of things turned up at Hammershus -- keys, coins, canteens. Coins are usually useful when it comes to dating, but in this case the spread was from the 13th century and onwards. The objects came from the castle’s entire life span, so this hotchpotch did not reveal when the castle was built,” he says, adding that the new dig will be entirely different and systematic.
Among other things, the researchers will remove five-centimetre layers at a time so as to keep tabs on the chronology and what they find, so that they can compare the objects found in the same layer. Our forefathers also used grandma’s old pots just as we do today.
If the researchers are to form some kind of picture for dating they need to keep tabs on which layer the remnants are found in.
Ancient legend may have a grain of truth in it
Engberg has no doubt as to what he hopes the result will be:
“I believe that Hammershus was built in the 12th century or early 13th century by one of the Valdemars as a regal installation where the expeditionary fleet gathered, the Crusaders met before heading for Estonia, which is where, according to legend, the Danish standard flag Dannebrog fell down from heaven. That’s the best story in my opinion. And if it’s also right then there actually was a grain of truth in the legend about Hammershus. I have to say, though, that we have to keep our options open,” says Engberg.
