There was extensive trade between Scandinavia and the Mediterranean, and some of the vikings are believed to have been Muslims from the Middle East and North Africa (“viking” meant armed seafarer, and was a profession and not an ethnicity). Meanwhile, Norse and Icelandic mercenaries worked as the Byzantine empire’s Varangian Guards (they were favoured for their courage, and equally importantly, lack of connection to domestic political intrigues).
Ok, as someone who was genuinely interested in Scandinavian history during the Viking Age, this one pisses me off more than it should, we know the vikings at BARE MINIMUM LEVEL OF CONTACT traded with people who traded with the Arabs, we know this because several viking hoards have been discovered with Arab coins.
Additionally, the Viking era came about because the vikings had (generally) better boats than other countries at the time, and those boats could traverse both river and sea, allowing them to trade over great distance.
There's a ton of other stuff I wont go into about the steel (which, by the way, was not damascus, nobody who spent any time learning about it would claim so), the broad terminology of "vikings", and the Ulfbert sword, maybe I'll come back some day and type it out, but I just don't have the time or energy to write an essay right now