Answer:
Africans played a direct role in the slave trade, kidnapping adults and stealing children for the purpose of selling them, through intermediaries, to Europeans or their agents. Those sold into slavery were usually from a different ethnic group than those who captured them, whether enemies or just neighbors.
The Tang Dynasty of China when faced with rebellion from General An Lushan in their northern territories sought outside support from mercenary forces. This was done a number of times during the rebellion, these mercenaries were typically Arab, however, we also have examples of soldiers brought from Uighur to fight with the Tang and numbered in the thousands in the fight against Lushan's forces.
With the help of mercenary forces, the Tang were able to take back several important capital cities of China and effectively eliminated the rebellion of Lushan, as well as his later supporters and successors.
States of the German Confederation
Archduchy of Austria (split into Upper Austria and Lower Austria in 1849)
Kingdom of Bohemia.
Margraviate of Moravia.
Grand Duchy of Salzburg.
Duchy of Carinthia.
Duchy of Carniola.
Duchy of Upper and Lower Silesia.
Duchy of Styria.
