Wanda wrote "Ulf did you use the Old Greek Roman Alphabet to decipher it? :)" No, it isn't sure that I have right, it's just a guess.
The combination of XOX is a likely runic type of spell for good luck, meaning that it replaces the actual letters in the sentence. Then both in the beginning and the end of the line , is a double sword in cross, that suggest either knighthood, or a relation to crusaders, or in fact both.
Likely, it could also depict the letter K, as an initial to the owner.
It could also have been written by someone with less experience in writing, making simple mistakes. ex. The(that) honor to (that) this sword
-ad illi gladii id honore- or I have totally wrong and it's not Latin at all,
the writing becomes something else, ending with Noriek?
But I see why they have problems with it and why it's like a riddle.
There was some noble men who had double swords in their shields at this time, both in England and West Germany, but I would have to see a lot more writings on swords in order to compare the styles.
About the sword. It seems to be from the period of 1200-1300, it is of highest purity, light and most likely also very expensive. Nothing for a commoner, this I can see.