Well rather, Bediouns are a ethnicity, as I am Bedioun myself.
I am speaking more directly of the warrior caste of my ethnic group, of which has served as Mercenaries, and are Nomads who refer to eithier total nomad or semi nomad lifestyles of which involve herding.
(although Alot of Bediouns, such as myself have settled now obviously. But there is just as many traditionalists going about)
Bedioun warriors not only served in Desert regions, but have served in Europe, Africa, and other parts of Asia as well.
A great example of this was in the 14th Century when the Ottoman Turks hired Bedioun Warlords to support them in Wallachia. THe few victories held by the Ottomans included Bedioun warriors each time, and every time. And thats due to the fact they used Bedioun Warriors as a sort of Geurilla to counter Geurilla warfare used by Vlad Dracul II at the time.
Another example is when the Abyssinian Mountain Kingdoms of Africa in the late 18th Century (some of the few ones still independent)
Waged war with each other. These nations included Malinda, Gallia, And Gondar. These nations, the most powerful of all of them, Gondar was overrun by a Gallia armed force, of which were known Savage warriros of the time, combined with Gondars most powerful co leader, who was exiled due to adultery with the Gondar Royal Empress (Who was considered sacred)
The Archbishop of the Gondar Christian Church, the Acab Scat, Lead a coup to overthrow them.
If needed I will explain these kingdoms more, but this generally took place in the area of Ethiopia, Sudan, and nations surrounding it.
However, the Daughter of the Empress managed to escape the massive invasion, and later after evading the Acab Scaats Bounty Hunters for qutie some time, and with refugee Malindan Royalty, managed to find allies along freed Slaves, as well as a BEDIOUN Radical who led his tribe with a few other groups, and drove across Malinda, gathering people to their cause (the Gallia were oppressive, and + the fact they had Malindian Royalty, the people rose up)
And joined the cause. After pushing the Acab Scaats forces out of Malinda, and with little time to lsoe before the Acab Scaat withdrawed his forces that were attacking nearby regions, The Empress moved to reclaim her throne. After a tough, gritty seige, which involved infiltration, Bedioun forces combined with Many African tribes stormed through the city of Gondar, pushing back the Gallia. The Acab Scaat decided to hole up in the restored City Fortress tower, and it took to a few brave infilitrators to climb through the tower, and kill him.
Also, Wars involving the Timurids, Mongols, and as well as the Crimean war involved Bediouns.
Varangian Guards on the other hand, seemingly died out after the Tatars invaded Russia, overthrowing the first Slavic rulers of Russia, and it wasn't until succsessive leaders, inlcuding Ivan the Terrible, that the Tatars were fianlly driven out.