Rope/Knot work for borders

[Crayons]

Historical "influences" across that entire period are likely to be widespread! The actual attribution of styles and methods is probably rather futile!
The Celts themselves didn't start in Ireland/Wales/Normandy anyway. That's just where the last pockets of the culture are still maintained. At some point it appears that "preservation" becomes an issue, superceding the previous cultural exchange aspects.

Like many cultures in Europe it's all rather messy historically

[Gamerprinter]

Historical "influences" across that entire period are likely to be widespread! The actual attribution of styles and methods is probably rather futile!
The Celts themselves didn't start in Ireland/Wales/Normandy anyway. That's just where the last pockets of the culture are still maintained. At some point it appears that "preservation" becomes an issue, superceding the previous cultural exchange aspects.

Like many cultures in Europe it's all rather messy historically

As far as we know the Celts started with the Halstatt culture which was in the Danube valley and in Switzerland. And the Celts had moved to Spain, Po Valley Italy, the British Isles, Gaul/France, Galacia in Turkey and evidence exists that the Celts made it northern India.

Regarding the knotwork, Celts used rune symbols and swirls and other geometric figures as notable in stone carvings and other media, but noticeably no knotwork.

The Teutonic styled art - including viking art, saxon art does show evidence of knotwork used, so that is where I get my historical point. While its true that most European cultures come from a probably Indo-European original race (as language indicates this is true), the cultural art taken by various peoples are different enough to recognize some root source. Celtic knotwork is not Celtic by historical evidence.

[Crayons]

As far as we know the Celts started with the Halstatt culture which was in the Danube valley and in Switzerland. And the Celts had moved to Spain, Po Valley Italy, the British Isles, Gaul/France, Galacia in Turkey and evidence exists that the Celts made it northern India.

Regarding the knotwork, Celts used rune symbols and swirls and other geometric figures as notable in stone carvings and other media, but noticeably no knotwork.

The Teutonic styled art - including viking art, saxon art does show evidence of knotwork used, so that is where I get my historical point. While its true that most European cultures come from a probably Indo-European original race (as language indicates this is true), the cultural art taken by various peoples are different enough to recognize some root source. Celtic knotwork is not Celtic by historical evidence.

I don't disagree with you on it not being Celtic, but to conclude it's Danish is probably a similar mistake to the Celtic one. You could also attribute it to Byzantine or Roman origins or, since the Celts "moved through" the Denmark area in their travels they may have "left" that design behind. It's not really all that important IMO, it is essentially the art of tracking "fashion" which strikes me as vaguely pointless exercise since it only really identifies trade communications - which we already know were widespread thoroughout the dark ages and long before.
They still look good though!!