The saga of humanity is, in many ways, the saga of conflict. From tribal skirmishes over fire to modern wars over oil, the drive to fight has produced a handful of truly legendary fighting forces. In this roundup we spotlight the top 10 best armies, legions, and squads that have repeatedly turned the tide of battle, inspired fear in their foes, and left an indelible mark on world history.
Why These Units Earn the Title of Top 10 Best
Each of the forces below earned its reputation not just through sheer numbers, but by mastering tactics, technology, and morale in ways that made their enemies think twice before charging. From disciplined infantry to daring pilots, the common thread is excellence on the battlefield.
10 The Immortals
The Persians fielded a uniquely disciplined unit known as the Immortals, a corps of exactly ten thousand men—no more, no less—who could be instantly replenished to maintain that precise strength. Their reputation for unwavering presence made them a psychological weapon; opponents often imagined a wall of relentless warriors that never waned. Though they wore only modest armor, their confidence and coordinated shock tactics made them terrifying opponents, especially when they struck from unexpected angles.
During the famous clash at Thermopylae, the Immortals attempted to outflank the Spartan defenders by attacking from the rear, showcasing their strategic flexibility. Across numerous campaigns of the Achaemenid Empire, they consistently emerged victorious, cementing a legacy that outlived the mythic Hollywood portrayal in the film 300. Their name, “Immortal,” truly reflected the enduring fear they inspired on the ancient battlefield.
9 Thessalians
When Alexander the Great set his sights on Persia, his success hinged not only on his own brilliance but also on the elite cavalry he inherited from his father, Philip II, after conquering Thessaly. The Thessalian horsemen were celebrated for their disciplined formations, especially the distinctive rhomboid shape that made them exceptionally hard to break compared to the typical wedge formations used by other armies.
These cavalrymen fought alongside Alexander in every major engagement of his Asian campaign, from the Battle of Granicus to the decisive showdown at Gaugamela. Their ability to hold formation under pressure and execute rapid, coordinated charges earned them a reputation for near‑invincibility, and their loyalty to the Macedonian king ensured they were a decisive factor in his unprecedented conquests.
8 Genoese Crossbowmen
The medieval battlefield saw a revolution in ranged weaponry, and nowhere was this more evident than with the Genoese crossbowmen. These specialists mastered the powerful crossbow, a weapon capable of penetrating the heavy armor that defined the era’s knights. Their skill made them highly sought after as mercenaries, and they frequently fought for diverse powers across Europe.
One of their most dramatic victories occurred at the Battle of Parma, where they helped a papal‑aligned force crush the Holy Roman Empire’s troops, earning such infuriated enemies that the emperor ordered the severing of their fingers to cripple future use of the crossbow. Yet the Genoese persisted, remaining a feared component of European warfare until the rise of gunpowder rendered their craft obsolete.
7 Nordic Housecarls
When the Vikings crossed the North Sea to raid and settle in England, they brought with them a formidable elite known as the housecarls. Originally personal bodyguards to Scandinavian monarchs, these warriors became integral to the English royal courts after King Cnut of Denmark secured the English throne. Their reputation for brutal efficiency and unwavering loyalty quickly spread throughout the British Isles.
Equipped with razor‑sharp battle axes, spears, swords, and the iconic kite‑shaped shield, housecarls fought in full mail armor, making them a terrifying sight on the battlefield. Their role expanded beyond pure combat; they also served as administrators and senior officials, blending martial prowess with political influence—a hybrid that resembled later European knights in both function and status.
Throughout the centuries, successive English kings retained housecarls as a core component of their standing armies, relying on their disciplined ferocity to protect the realm and enforce royal authority.
6 Argyraspides
Among Alexander the Great’s most elite formations were the Argyraspides, literally “silver‑shield bearers.” Legend holds that the silver plating on their shields stemmed from a prophetic oracle foretelling world conquest, a testament to the symbolic weight of the unit. Formed during Alexander’s final Indian campaign, these veterans were seasoned soldiers, often over fifty years old, whose experience made them the king’s most trusted battlefield companions.
Armed with the classic Macedonian dory spear and protected by gleaming shields, the Argyraspides served as personal bodyguards and frontline shock troops. Their age and battle‑hardened wisdom earned them a place of honor in the later Hellenistic kingdoms, particularly the Seleucid Empire, where they continued to influence military tactics long after Alexander’s death.
5 Almogavars
In the thirteenth‑century Mediterranean, the Crown of Aragon’s Catalan territories produced a fierce, lightly‑armored force known as the Almogavars. Drawn from the rugged mountain regions, these mercenaries excelled at guerrilla tactics, night raids, and swift movement across difficult terrain, relying on minimal armor for speed and surprise.
Their reputation grew as they fought across the Iberian Peninsula, the Byzantine Empire, and even against the Ottoman Turks. Notably, they played a pivotal role in the reconquest of key strongholds and in battles that shifted the balance of power between Christian and Muslim forces in the region. Their adaptability and ferocious fighting style cemented their status as one of the most effective mercenary units of the Middle Ages.
4 Tuskegee Airmen
During World War II, the United States faced a stark paradox: a war for freedom fought by a military that still segregated its own troops. The Tuskegee Airmen, a cadre of African‑American pilots trained at the Tuskegee Institute, shattered both enemy defenses and domestic prejudice with their extraordinary performance.
Initially tasked with escorting Allied bombers over hostile German skies, the airmen quickly proved their mettle by downing enemy aircraft while protecting their charges. Over 15,000 sorties yielded 261 confirmed German kills and 150 Distinguished Flying Crosses. Though later research revealed that a few bombers were lost, the overall record remains one of the most impressive in aerial combat history, earning them a Congressional Gold Medal in 2007.
3 Caroleans
Sweden’s golden age in the seventeenth and eighteenth centuries owed much to its shock‑troop infantry, the Caroleans, named after King Charles XI. These soldiers combined bayonets, pikes, and rapiers, training relentlessly for aggressive, forward‑focused assaults rather than defensive posturing.
Their ferocity shone at the Battle of Narva, where a modest Carolean force decimated a Russian army four times its size. Though the Swedish empire eventually faltered after a disastrous winter campaign in Russia, the Caroleans’ reputation for fearless, offensive tactics persisted, leaving a lasting imprint on European military doctrine.
2 Knights Hospitaller
While the Knights Templar often dominate popular imagination, the Knights Hospitaller carved out a distinct, formidable legacy. Originating in the early eleventh century as caretakers for pilgrims in Jerusalem, they evolved into a militarized order after the First Crusade, defending Christian holdings against Ottoman expansion for centuries.
The Hospitallers excelled both on land and at sea, raiding Turkish vessels and leading decisive assaults in numerous Crusades. Their mastery of swords, lances, and maces—combined with a disciplined, religiously‑motivated ethos—made them a cornerstone of medieval Christendom’s military might, persisting well into the eighteenth century before the Napoleonic era curtailed their influence.
1 Reislaufer
Switzerland’s famed neutrality masks a storied past of relentless pike‑warriors known as the Reislaufer. These mercenary pikemen earned a reputation for unwavering resolve, repelling Habsburg invasions and defending the nascent Swiss Confederacy with sheer tenacity and coordinated pike formations.
Their battlefield success attracted the attention of European powers, who hired them en masse as elite infantry. The Reislaufer’s mastery of the pike, complemented by halberds, swords, and war clubs, allowed them to dominate cavalry‑heavy armies until firearms gradually rendered the pike obsolete. Their legacy endures as a symbol of disciplined, fearless infantry.
Himanshu can be found shouting obscenities at strangers on Twitter @RudeRidingRomeo or making amateur drawings on Instagram @anartism_. Has written for Forbes, Cracked, Modern Rogue, and Screen Rant. Pay him money for writing stuff for you here: [email protected]