When speaks of the slavery he means the white slave trade. Slave even means slav, because of how many slavs were enslaved by the vikings and sold in north africa
There was a massive white slave tradebetween Europe, Central Asia and the Middle that lasted over 1,000 years. This brought an enormous number of white Western and Eastern Europeans into the Middle East.
(The focus on African slaves in Arabia only came after access to white slave trade routes was lost.)
“In the Viking era starting c. 793, the Norse raiders often captured and enslaved militarily weaker peoples they encountered. In the Nordic countries the slaves were called thralls (Old Norse: þræll) The thralls were mostly from Western Europe [i.e. Far West Asia], among them many Franks, Anglo-Saxons and Celts… There is evidence of German, Baltic, Slavic and Latin slaves as well. The slave trade was one of the pillars of Norse commerce during the 6th through 11th centuries.”
“Slavery during the Early Middle Ages had several distinct sources. The Vikings raided across Europe, though their slave raids were the most destructive in the British Isles and Eastern Europe. While the Vikings kept some slaves for themselves as servants, known as thralls, most people captured by the Vikings would be sold on the Byzantine or Islamic markets. In the West the targets of Viking slavery were primarily English, Irish, and Scottish, while in the East they were mainly Slavs. The Viking slave trade slowly ended in the 1000s…”
“The Middle Ages form 1100 to 1500 saw a continuation of the European Slave trade, though with a shift form the Western Mediterranean Islamic nations (Andalusian Spain, modern day Morocco) to the Eastern, as Venice and Genoa, in firm control of the Eastern Mediterranean from the 12th century and the Black Sea from the 13th century sold both Slavic and Baltic slaves, as well as Georgians, Turks and other ethnic groups of the Black Sea and Caucasus, to the Muslim nations of the Middle East. The sale of European slaves by Europeans slowly ended as the Slavic and Baltic ethnic groups Christianized by the Late Middle Ages. European slaves in the Islamic World would, however, continue into the Modern time period as Muslim pirates, primarily Algerians, with the support of the Ottoman Empire, raided European coasts and shipping form the 16th to the 19th centuries…”
“Genoese merchants organized the slave trade from the Crimea to Mamluk Egypt.”
“For a long time [from declaring independence in1441] until the early 18th century, the [Crimean] khanate maintained a massive slave trade with the Ottoman Empire and the Middle East. In a process called the “harvesting of the steppe”, they enslaved many Slavic peasants.”
“The Byzantine-Ottoman wars [in or near modern Turkey] and the Ottoman wars in Europe brought large numbers of Christian slaves into the Islamic world too.”
Asaolu, Richard Oluseyi. Slavery. PediaPress. pp 4-7.
http://books.google.com.sa/books?id...Richard+Oluseyi+slavery&source=gbs_navlinks_s