The rats nest that is Islamic slavery has a dimension that included  
over a million Europeans from the early medieval to the 19th century.  
Apparently whole villages of Irish were carted off and sold into  
slavery in Morocco and other parts of the Barbary Coast in the time  
that it was ongoing. An example in print is:

White Gold

The Extraordinary Story of Thomas Pellow and Islam's One Million  
White Slaves

By Giles Milton

Jefferson's solution using military force was also done by Britain.  
Their combined efforts stopped the seafaring raiders but of course  
did nothing for the land-based janjaweed equivalents.

Lyle Browning

On Jun 13, 2007, at 10:03 AM, Jurretta Heckscher wrote:

> By way of a p.s. to this discussion:   If you read Lovejoy or other  
> works that discuss the Islamic trade in slaves from Africa to the  
> Middle East, you may be--as I was--amazed to learn the huge numbers  
> that were involved.  Millions of Africans were caught up in this  
> trade, though always many fewer than in the Atlantic trade (and  
> it's worth mentioning that in the Atlantic trade, North America was  
> a minor, peripheral destination: the vast majority of slaves went  
> to the Caribbean and, later, to Brazil).
>
> The critical distinction between the Islamic/East African and  
> Atlantic trades, however, from the standpoint of historical  
> consequences, is that the children of African slaves in the Middle  
> East, and even some of the slaves themselves, were fully  
> incorporated into society.  Such incorporation has been the norm in  
> most slaveholding societies throughout history.  It is the race- 
> based, perpetually heritable dimension of Atlantic slavery that  
> sets it apart historically from other slave systems and determined  
> its role in New World societies.
>
> --Jurretta