Before the rise of Macedonia, Rome and Carthage; the most noticeable empires of the Mediterranean and North Africa were the Egyptians and the Persians. Egypt lasted almost 3000 years before falling to the Persians, and that Persian Achaemenid Empire was estimated to rule about 44% of the world’s population at that time (Modern day China, India, USA and Indonesia combined make up about 44% of the world's population.)
What I want to focus on is how the Egyptians created the basics of Bronze Age warfare as well as how the Persians perfected such technology: primarily with Chariot warfare. However since the Persians conquered the Egyptians, and were more successful in empire-building, I will focus on the Persian Immortal primarily.
Horseback riding has existed since prehistory, but was initially concentrated primarily in the Eurasian Stepp: hence why the Huns and Mongolians have long histories of horse warfare. About 2500 BC: Chariots were created in the Middle East. From what I researched: Chariot horses are too small to have a rider on them and so initially; the Middle East only had Chariots due to this handicap.
This was still a massive advantage in combat due to the speed advantage: Chariots can maintain a speed of about 20mph. While Usain Bolt can sprint 27.8 mph, this is only a sprint for a person with absolutely no gear or weapons. Marathons are normally done at about 10mph; again, without additional weight for the runners. (Human walking speed is 2.5 mph BTW.)
The best way to defeat an enemy army, assuming both sides have identical units, is to outflank and surround them. The army is forced to face an enemy attacking from multiple sides, and the corners of the army are pinched away as these soldiers have to face attacks from their left, front and right simultaneously.
The idea of rushing the enemy like this is perfect for a War Chariot. If there is one noticeable advantage a Chariot has against a Horseman is offensives weapons; a Chariot of 3 men (1 being the driver driver) can use 1 bow, 1 spear and 1 pair of Chariot Scythes simultaneously. The only way to block this would be with a very heavy metal shield: and the Chariot will just maintain its distance with its speed and try to outflank the tanky shield and use its arrows.
Now in regards to a War Chariot Scythe; there’s a lot of debate over its lethality. Tests I’ve seen mostly conclude that scythe is not sharp enough to kill if it strikes the torso, and that since it’s aiming for the legs, it’s not striking vital organs when it hits. However, I think an important factor is being ignored here: incapacitation. A 20mph blade with the inertia of a small car is going to severely mangle anything it hits. If your legs are that mutilated, you can’t even walk: how do you fight back if you’re bleeding out and YOU CAN’T STAND? Keep in mind that, especially during the Bronze Age, legs were rarely fully armored. Now I have no idea what would happen if you tried to block a Chariot Scythe with a shield, but the blunt force of the impact is going to be a factor.
The weapons of the Immortals allowed them to be effective in any scenario, as seen with the Pesrian Spear (Arsti): it can be used on Chariot, on foot with, or without a shield. Both the Arsti and Sagaris have a piercing point and a blunt point: both of which can be used effectively. The Sagaris is not only a reasonable side-arm but has both the blunt force and piercing spike of a war-hammer to damage enemy armor: it is essentially a prototype of a medieval war-hammer.
Finally a quick nod to the Scale Bronze armor. While the limbs are mostly unprotected, the chest is still decently protected. Bronze is still hard enough to take a hit, and the Scales can be easily replaced after a battle. I will mention though that this armor is too thin to tank a heavy or repeated blow, but it is fair considering that Persian deserts would make any heavier armor overheat.
Chariots were one of the first advanced modes of transportation, but it also quickly fizzled out. Until the car was invented; Chariots were basically converted into wagons and only used for transport. As epic as they might appear, Chariots have plenty of flaws.
Chariots cannot be used effectively if the enemy can defend their flanks, uses natural barriers or engages on a narrow battlefield (as seen in The Battle of Thermopylae) or if they manage to get outflanked themselves. The Persians are lightweight warriors anyways, and so are somewhat dependent on Chariot support to complement their relatively mobile forces: the front lines of a lightweight army can collapse if they can’t exploit the flanks (as seen with The Battle of Marathon). Alexander the Great also created counters against Chariots: in The Battle of Gaugamela, he had his soldiers create gaps in the line to dodge a charging Chariot and thus completely encircle them.
But the bigger issue with the Chariot is simply put: horseback riding is so much better. The average Chariot can go about 20mph Chariot, but a horseman can ride 30pmh: a Chariot is additional weight for a horse and slows it down. The wheels of a Chariot also lack maneuverability and can be crippled by certain terrain; shallow water, mud, steep hills… The Chariot needs two soldiers, and a large Chariot has at least 2 horses. So you are wasting twice the horses and men to use a vehicle that is slightly slower and limits one of the two men as you need a driver for the Chariot. Horsemen can use their feet to ‘drive’, hence why cowboys had spurs on their boots: which means they can use their sword or bow without wasting a second soldier to be their driver.
If 1 Chariot was fighting 2 Horsemen; the Horsemen will outmaneuver and overpower the Chariot with relative ease. The Chariot’s only advantage, the Chariot Scythes, would not compensate the disadvantages.
Let’s also look at the Persian Immortal on foot. His weapons are standard and relatively light, but they all work. The issue is defenses: the Immortal is designed for desert combat and so has struggled to invade Greece: where a cooler climate allows for heavier Hoplites to have superior armor and shields. The film 300 is laughably stupid, but the idea that a Spartan can overpower a Persian Immortal is indeed fact. The Persian Scale Armor is significantly inferior to a solid Muscle Cuirass. And of course you have that Gerron Wicker Shield: damn these Wicker Shields. It’s decent for lightweight weapons, but Spartans are basically the tanks of the Bronze Age. I heard that Persians used the Greek Aspis in future battles, knowing that the Gerron sucks against heavy Greek Pikes.
The fact that Alexander was able to overwhelm the Persians shows that Hoplites are a great counter against the Immortals; even if you point out the fact that Macedonians used armor and shields that were lighter compared to the Spartans. Rajputs resisted Persian invasions, and the Mongolians conquered Persia: both of these make sense since these warriors have good armor and can use heavy armor-piercing weapons while still being light enough to withstand the desert heat.