How did pastoral nomads keep winning battles/wars? When did the tide turn against them for settled societies?

Pastoral societies dominated at roughly the same time that "cavalry" dominated, roughly from the middle of the first millenium to the middle of the second millenium. This was due to the invention of the "modern" stirrup, which in turn depended on a solid "saddle tree" to hold it in place. The stirrup meant that mounted soldiers with equal weapons to infantry (lance or bow and arrow) would enjoy an advantage over infantry, because of the greater speed and velocity of their "transportation." Pastoral people, by definition, used horses a lot more than "settled" people.

This advantage was eroded with the invention of gunpowder, and completely nullified with the introduction of "repeating" rifles. That's because "guns," unlike hand weapons, were easier to manage by footmen than by mounted men, thereby offsetting the advantages that the horses gave to the latter.

I think a very obvious reason is that nomads had fixed targets, i.e., settlements/cities to attack. By their very nature, such cities were not mobile and so it is immediately clear who the would be on the defensive and who could attack and withdraw at will. This is an almost insurmountable advantage as seems to be borne out by the observation of the original questioner. It is only when the settlers have an army with a large enough force to actually wipe out or compel resettlement of the nomads that their advantage is overcome. Mexico well into the 19th century was basically at the mercy of warlike Indian tribes, paying tribute to them even though Mexico had a modern army with artillery (which is not nearly as effective against moving targets as it is against fortifications which of course the Indians did not have) and superior firearms for the most part. Mexico benefited (in this respect) by the expansion of the United States which displaced or wiped out these tribes.

I would add that settled peoples had in a sense much more to lose: they had invested vast amounts of time and capital in building their cities and this would make them more likely to surrender and pay tribute rather than risk their loss: in general, it is much easier to destroy than to create: a vandal (in the modern sense of the word) with a match can a destroy in hours a building which took months or years to build.

Generally speaking, nomadic invasions succeeded when the political and economic conditions were bad enough to allow it. When conditions improved, the nomads were dealt with.

The border of China with Mongolia was the site of the most intense nomadic warfare because of their proximity and lack of practical barriers. China was an ongoing target of nomads in Mongolia, and nomadic warfare forms a constant theme in Chinese history. The situation was almost as "intimate" in Central Asia, where the silk road oasis cities were located. Still, though, the nomads only succeeded during low points for the economies and politics of these regions.

Europe was more of a back door for nomads that had been defeated and driven off of the steppe. Nomads brought new technologies from Mongolia and China that gained them a temporary advantage in the West. Eventually, the westerners were able to adopt the technologies themselves.

The Visigoths (1) introduced the shoulder harness, prior to which Romans had used a simple strap around the neck that restricted the horse's aeorta. The origin of this invention is uncertain, but the oldest attested horse harness is from about 300 B.C. in China. This new type of cavalry forced the Romans to focus away from infantry and towards heavy cavalry. Before they were able to do this, around the turn of the fifth century, the Romans suffered a number of heavy defeats by the Goths. The Romans began to incite Germanic, but also nomadic political rivalries, as well as paid tributes, which turned the tide. Nomads were also not good at sieges, as exemplified by the ineffectiveness of the Avars at the siege of Constantinople in 627.

The next major advancement in cavalry was the invention of the stirrup and hard soles. Its origin is also unclear, but it originated somewhere in the vicinity of Mongolia or China. The Griffin and Tendril Culture brought stirrups to Hungary around 800 A.D. It was limited to this area until the Magyar invasions of Europe, which sprung another change in European cavalry tactics.

Nomads rarely ever invaded Europe voluntarily. Nomadic warfare on the steppe created demographic pressures that pushed desperate tribes into areas of western civilization (2). Broadly speaking, a confederation of nomads would be defeated in Mongolia and move to Northern Iran. Further pressures would put them in Ukraine, and eventually Hungary, where they invaded Europe. These forces also led to the influx of Turks into Central Asia that would become Mamluks, Qara Kanids, and Seljuks. Warfare in Mongolia peaked following the fall of the second Khaganate, until about 1200, and accelerated these forces. Once they entered into civilized regions, the complex process occured whereby they would assimilate.

Nomads were commendable for their speed, but they also used unconventional hit-and run tactics. They would travel in bands and attack sporadically, being quick to retreat when necessary. The use of the feigned retreat was an invention of nomadic warrior; by faking a retreat they would draw the opponents out of their formation. The Alans were especially adept at this, and had a reputation that almost made it pointless to fight them. These tactics, and especially the feigned retreat, are complicated because cavalry can easily become scattered and incoherent.

Another skill used by Scythians and Sarmatians was their ability to shoot backwards while retreating. This difficult maneuver is portrayed in the classic Scythian metal work of the steppe where the rider is shooting back over his shoulder. Hunnic people are an exception to this description of a highly specialized warrior; instead they relied on numbers, as well as other skilled cavalry like the Goths.

The Romans and Chinese were able to take advantage of political rivalries of barbarians and nomads. Their ability to ally with them by paying them tribute turned out to be a successful form of diplomacy. The Byzantines did this successfully until the fall of the Khazar Khaganate in 965. Don't forget that the nomads eventually prevailed against the Byzantine Empire by establishing the Ottoman Empire.

The invention of gunpowder was an obvious advantage over nomadic peoples. However, the age of exploration and the closing of the silk road ended a chapter in Asian history from which the nomads belonged to. The Iranian oasis cities along the silk road, which had played a formative role in the creation of the various nomadic empires (3), receded into obscurity, and the region became devoid of wealth.

(1) Goths are included because they adopted the material culture of the Scythians, whom they conquered.

(2) The arrival of the Alans in Sarmatia was triggered by the Xiongnu. Priscus the elder described the chain of events that led to the arrival of the huns in Europe. Later, the Avars were defeated by the Turks and arrived in Hungary. For the events from 740-1100, see The Migration of the Oghuz academia.edu

(3) Kasgari "a Turk without an Tat [Iranian] is like a head without a hat". This is exemplified in the Mongolian Empire by its administration by Khwarazmian bureaucrats. Golden, Peter. Turks and Iranians, A Historical Sketch.

Allow me to start with a caution:

From the Huns to the Mongols, pastoral nomads keep coming up in history books. Entire empires have fallen to them, ....

I think we need to be careful here. In general, most of the history books until late-20th century, especially on martial prowess of steppe nomads, were wrong (more below).

Question 1:

What advantages do the nomads possess ...?

Rephrase: What advantages do the nomads possess over the settled societes?

Simple Answer:

For steppe nomad in general, more horses because of the steppe. And, to some extent, better at art of horsemanship and composite bow that was, for the Turco-Mongols, extremely well-ranged for its time (exceeding 500 metres).

Inventions/Creations of Steppe Nomads in Warfare

• Horse domestication
• Composite bow
• Heavy cavalry troop (not individual)
• Organised cavalry (disciplined fighting in group)

The main instruments, horses and composite bow came from steppe nomads. Domesticated horses by Botai culture (around 3500 BCE). Composite bow not sure whom, around 1500 BCE. Heavy cavalry too, late 4th century CE, by the Xianbei tribe of Toba (or Tuoba Wei (拓跋魏) of Northern Wei). The stirrup for lancers appeared slightly earlier in north China/eastern Mongolia, early 4th century. The last point is organised cavalry, probably also around the time of invention of composite bow, 1500 BCE.

Botai culture of early Bronze Age (3700-3000 BCE), living around (modern-day) northern Kazakhstan is not the only source of domesticated horse. There is another but we still don't know this other source of domestication.

Side-note: Heavy cavalry troop (i.e. organised heavy cavalry) of Xianbei tribe of Toba in north China were contemporaneous or a few short decades after the appearance of the Huns in Rome's eastern front. Yet, Huns' heavy cavalry (of lancers) is not generally accepted as a troop. I suppose the evidence is missing. An excellent article on horse armour of the medieval Middle East (2017).

Question 2:

When did the tide turn against them for settled societies?

With the advent of gunpowder (from China) and better small arms (improved on by the West), from around mid-15th century onwards, the advantage of steppe warriors began to wane. Improved fortifications (in settled societies) against gunpowder weapons also increased its resilience against steppe nomads.

Were Steppe Nomads Better Natural Warriors?

Not asked, but implicit in question. The short answer is No, they were not born natural warriors. As for them "keep winning battles/wars", modern historians have shown that neither their culture nor their lifestyle makes them natural warriors, they were mostly defending themselves (against settled societies).

Putting it another way, they are certainly accustomed to act as defenders of livestock, but that is not the same as warrior-tribes rampaging incessantly against settled societies.

Finally, "From the Huns to the Mongols, pastoral nomads keep coming up in history books" - until last last few decades (late 1980s/early 1990s onwards) - most of the history books were wrong about the steppe nomads.

In some cases, the myth and misrepresentation of steppe warriors still persist to this day. For instance, the famed slave warriors of the Ayyubids, the Mamluks -- were not slaves (nor property). According to Beckwith, they are better described as comitatus - an elite group of warriors protecting a leader.

The key factors were high mobility and better weapons. The Huns for example were in the beginning almost exclusively mounted. Hunnic infantry appears much later. They were armed with a very powerful composite bow. The Sarmantians also had mainly cavalry, in their case heavily armored and armed with the kontos, a kind of sword on a stick or lance with a long blade on it.

Being mounted without much infantry gave them the advantages of surprise plus mobility, and the opportunity to withdraw when things didn't go their way, which did happen.

Their weapons also gave them advantages. The Hunnic bow was highly effective, and out ranged most bows of their enemies. Sarmantians were feared even by the Romans for the armor they wore and their long reach weapon. It was very difficult to kill a Sarmantian on horseback, while for the Sarmantian the opposite was true. Sarmantians were of course far less mobile than Hunnic cavalry.

Once they settled down they lost those advantages. Agriculturists must defend themselves everywhere. Nomads only had to defend their wagons. If the enemy burned the fields, no big deal. Just move to a different area, which they would have to do anyway. Devastate the land of agriculturalists, and they starve.