Yes, the Arabs knew about the Vikings. Similarly old Sanskrit grammar texts in India refer to the Greeks. St. Thomas Aquinas extensively refers to Arab scholars like Avicenna and Averroes. The ancient world was more connected than we realise.
https://www.timesofisrael.com/groundbreaking-study-ancient-t...
"They journeyed from Greater Scythia by way of the Tyrrhenian Sea and the Pillars of Hercules, and dwelt for a long course of time in Spain among the most savage tribes, but nowhere could they be subdued by any race, however barbarous."
https://www.historyfiles.co.uk/FeaturesBritain/Medieval_Text...
Of course, this is a bit bizarre - but a good story!
And there were Buddhists in the Roman empire https://en.wikipedia.org/wiki/Zarmanochegas