The Fragmentary Annals of Ireland describe an expedition undertaken by several important figures in the Great Heathen Army (possibly some of Ragnar Lothbrok's sons) after their conquest of York around the year 867. Almost immediately after their victory, these vikings sailed south from Britain and Ireland and wound up raiding and plundering the Spanish coast until, at some point, they had reached Africa (the annals are sort of unclear where exactly in Africa this is; you have to keep in mind that in the medieval Irish imagination, the geography of the Atlantic world was laid out pretty differently than our own conception of it).

Upon reaching the African coast, the vikings engage a local force in battle before making off with a bounty of African slaves:

While he was saying that, they saw the Mauritanian forces coming towards them, and when the son who spoke the above words saw that, he leaped suddenly into the battle, and attacked the king of the Mauritanians, and gave [him] a blow with a great sword and cut off his hand. There was hard fighting on both sides in this battle, and neither of them won the victory from the other in that battle. But all returned to camp, after many among them had been slain. However, they challenged each other to come to battle the next day.

The king of the Mauritanians escaped from the camp and fled in the night after his hand had been cut off. When the morning came, the Norwegians seized their weapons and readied themselves firmly and bravely for the battle. The Mauritanians, however, when they noticed that their king had departed, fled after they had been terribly slain. Thereupon the Norwegians swept across the country, and they devastated and burned the whole land. Then they brought a great host of them captive with them to Ireland, i.e. those are the black men. For Mauri is the same as nigri; 'Mauritania' is the same as nigritudo. Hardly one in three of the Norwegians escaped, between those who were slain, and those who drowned in the Gaditanian Straits. Now those black men remained in Ireland for a long time. Mauritania is located across from the Balearic Islands.

What was the fate of these "black men" in Ireland? They may have been sold from the slave market in Dublin to Irish lords or wealthy commoners in the interior where they would have performed pastoral labour such as shepherding flocks. This kind of prolific plundering and slave-taking made Dublin one of the most important trading towns (with the largest slave market) in all of Western Europe during the Viking Age, which means that the Africans captured by those vikings could have been sold to a buyer anywhere in Northern Europe. It's quite possible that those Africans could have ended up in York, Scotland, Scandinavia or even Iceland!

OP and only comment so far are about people forcibly captured and brought to Europe. While I embrace the spirit of the topic, is it intellectually honest to refer to slaves and captives as "Europeans of color"?

Showing up late to the party to show off England's Immigrants! This little database is the University of York's medievalists' baby, and it's a spread of every tax taken from persons of foreign birth from 1330 to 1550. Besides being a wealth of information on the demographics of immigrants in the later middle ages, it shows off a number of Europeans of color who settled in England long enough to be taxed! Here are a few of the highlights:

• Jacobus Black, 1484, 'Indian'
• Benedictus and Antonia Calaman, 1483, 'Indian'
• Luke de la Ark, 1541, from Turkey

'Indian' here is a general term for anyone living in what we now call the Middle East, and everything east of that. A few more are not PoC in the strict sense, but Jewish people living in England after the expulsion, such as Simon Jude, 1441. The university gave a presentation on this exact subject with a lot more examples than I could find in just a cursory search of a few keywords, including a large number of other Jews and people identified as Saracens.

I have a couple of earlier answers that might interest people:

• After World War I and during the Jazz Age, Paris became a haven for African American expats who wanted to escape the Jim Crow South. What happened to those African Americans when Nazi Germany occupied Paris?
• Did any European states in the Middle Ages or Renaissance ever have a ruler of African descent?