The historical evidence suggests that Vikings primarily engaged in the slave trade during their raids on various regions in Europe. The slaves they captured were mostly from different European ethnicities and races, such as Slavs, Celts, Anglo-Saxons, and others. It is important to note that "race" as a concept in the modern sense did not exist during the Viking Age, and the classification of people based on race as we understand it today would not have been the primary factor in the Viking slave trade.
The Viking slave trade was driven more by the practice of raiding and capturing people during their expeditions. Slavery was prevalent in many societies during that time, and the Vikings were not the only ones involved in this trade. The slaves captured by Vikings were often sold to various markets, including those in the Middle East, including Muslim traders. However, it is crucial to recognize that the dynamics of slavery in history were multifaceted, and it is inappropriate to view it through a modern racial lens.
Slavery is a dark part of human history, and its victims came from diverse backgrounds, ethnicities, and races across different regions of the world. It's essential to approach the topic with historical context and sensitivity, understanding that slavery existed in many societies throughout history and impacted people of various origins.