The Battle of Thermopylae

Background – chaoticblackcat

Persian Emperor Xerxes spent four years preparing the Persian army for the invasion of Greece (Herodotus 415). His preparations included the promised bridge across the Hellespont and a canal through Athos (Cartledge 95-96). Herodotus asserts that “Xerxes ordered the digging of the canal out of a sense of grandiosity and arrogance” (417). However, news of Xerxes’ mobilization reached the Greek mainland, and it became fairly obvious that some form of a unified defense might be necessary (Cartledge 97). A delegation of Greek cities met to consider a “united resistance” and the resulting leaders were the Spartans, primarily due to their military skill and the fact that “they already headed the only non-religious, non-ethnic multistate Greek military alliance then in existence, the Peloponnesian League” (Cartledge 99, 105). However, many Greeks were not part of the resistance and ultimately cooperated with the Persians as Herodotus notes that many “gave the King earth and water” and details how, at the Battle of Thermopylae, a “Malian called Ephialtes” sold info to Xerxes, telling the Persian king “about the mountain path to Thermopylae” (448, 479).  Herodotus also writes that “anyone who claims that the Athenians proved themselves to be the saviours of Greece would be perfectly correct… Once they had decided that their preference was for Greece to remain free, it was they who aroused the whole of Greece (except those places which were already collaborating with the Persians)” (451). However, the Athenians were not present at the Battle of Thermopylae and likely escaped any potential consequences of being associated with its defeat.

Though it was the first major land battle of the Persians’ second invasion of Greece, the dating of Thermopylae has, like most ancient dates, undergone some severe speculation. Dr. Kenneth Sacks, a Professor at Brown University who received a Ph.D. in Ancient History from the University of California, Berkeley, summarizes the arguments in his article “Herodotus and the Dating of the Battle of Thermopylae.” He emphasizes that Herodotus uses “summer as a climatic description only” and not as the specific season we would be familiar with today (238). While it is generally accepted that the battle took place around the same time as the Olympic Games, there is dispute as to the actual dating of the festival partly because of the shortage of available evidence (234).

According to Sacks, the key pieces of evidence that are available limit the Olympic festival to the range of “late July to late September” (235). Sacks writes that the majority of historians would date the Battle of Thermopylae “about ten days after an Olympic festival culminating on the full moon on 19 August” (240). Cartledge is one of the supporters of this theory, believing that the Battle of Thermopylae took place in late August (1). However, Sacks writes that dating the battle in August contradicts the few dating clues that Herodotus does give in his account, such as his hint that “the Persian navy, having sailed into Phalerum nine days after the battle, engaged the Greek fleet at Salamis on the next day” (242). Sacks asserts that those historians who choose to try and maintain Herodotus’s account would likely place the Battle of Thermopylae sometime in September (241).

While the date of the battle might be debated, its location is not, though it must be kept in mind that the topography definitely has changed since the days of ancient Greece. Cartledge emphasizes that despite its modern appearance today, at the time Thermopylae was a narrow pass between mountain and sea (141). Named after the location where it was fought, Greek historian Herodotus asserts that the battleground of the pass of Thermopylae was chosen primarily because “it looked narrower than the pass into Thessaly” which they had previously abandoned (467). Herodotus asserts that the Greek allies judged it to be a good place to make their first stand against the Persians (468).

Present at the battle of Thermopylae and leading the famous elite Spartan force of three hundred was the Spartan King Leonidas who, according to Herodotus, was supposedly a descendent of Heracles (476). He would die on the battlefield (Herodotus 483). He was not the only one. Other Lacedaemonians (the region of which Sparta is capital) who gained fame through their bravery in combat and would die at Thermopylae were Dianeces, Alpheus, and Maron (Herodotus 484). Though they often do not get as much focus as the Spartans, the following were other commanders present at the battle’s final stand: Demophilus, the commander of the Thespians, and Leontiadas, the commander of the Thebans (Herodotus 482, 476). According to Herodotus, the most distinguished Thespian warrior to die in the battle was Dithyrambus (484). The Greek historian also notes that the Persian King Xerxes observed the battle and lived, but he wrote that two of Xerxes’ brothers, Abrocomes and Hyperanthes, did not survive (483-484). Those, however, are just some of the more memorable members of the wide range of combatants present at Thermopylae.

Main Combatants & Casus Belli – (honorstudent2016)

The Greeks’ Armor and Weapons

greeksPictured to the left is an illustration of a Greek hoplite (May et. al). Pictured to the right is an illustration of a phalanx formation (“Battle of Thermopylae”).


Greek soldiers, hoplites, were trained in the spear and infantry, specifically phalanx formation. Hoplites also used swords, termed xiphos, when their spears were of no use anymore in battle.  Characteristic of the hoplite image is the shield–it is circular in shape, made of wood, over 3 feet in diameter, and was coated in bronze and very heavy. These shields were crucial in the formation of the phalanx (“Ancient Greek Warfare”).



Persian (right) and Median (left) soldiers. (Happolati).

The Persians

The Persians had a large army, much larger than the Greek armies. Their weapons included bow and arrow, swords, knives, wicker shields, and short spears. Their armor consisted of scale coats underneath their robes. Persian soldiers also wore what is called “Persian tiaras.” However, it could have simply been a hood or hat pulled over the face to protect against wind, sand, and dust. Herodotus claims they “glittered with gold.” One infamous aspect of the Persian army is the elite group known as “The Immortals.” These soldiers were regarded as the best of the Persian army and were highly skilled and decorated in battle (Herodotus 7:83-84).



Casus Belli: Why the Greeks and Persians were Fighting


A Persian soldier (left) battling a Greek hoplite (right). (Άγνωστος)


To know why Greece was fighting with Persia, one must understand the initial offense. The beginning of Greek distaste for Persia involves the Ionian Revolt in 499 to 494 BCE. The Ionian people had been conquered in 560 BCE by Alyattes II, a Lydian king. He and his successor, Croesus, allowed Ionia to have independent rule of its own people with one exception: to obey Lydia in foreign matters. However, the Ionian people were not going to live in peace for long. Persia, under the rule of Cyrus, took over the Median Empire by utilizing Median rebels. Cyrus then set his eyes on Lydia and tried to inspire the Ionians to rebel, but the Ionians refused. Nonetheless, the Persians conquered Lydia in 546 BCE. Cyrus was not as gracious as Alyattes and Croesus to the Ionians; he held a grudge for them not rebelling against the Lydians. Ironically, Athens encouraged the Ionians to rebel, and the Ionian people listened and began to rebel against the Persian Empire in 499 BCE. Persia, under the rule of Darius I, punished Athens for encouraging the rebellion of the Ionians by invading and attacking Athens (“Greco-Persian Wars”).
Fearing the might and breadth of the Persian army, the Greek-city states decided to team-up to fight Persia, since individually they’d have no hope. In 480 BCE, the Greek city-states were already allied together in an effort to block the invasion of the Persians, now being led by their general and king Xerxes, who succeeded Darius I in 486 BCE (Cartledge 59). Themistocles, the Athenian general at the time, had a strategy to block the Persians army at Thermopylae and the Straits of Artemisium. The Spartan Leader, Leonidas brought his best soldiers and tried to inspire the other fighting Greeks. The Greeks quantified by Herodotus who were involved in this battle included: 300 Spartans, 500 Tegeans, 500 Mantineans, 120 Orchomenians from Arcadia, 1000 Arcadians, 400 Corinthians, 200 Phelioans, 80 Mycenaens, 700 Thespians, 400 Thebens, and 1000 Phocians and Locrians. Herodotus declares there were 2.6 million Persians (7:185, 202, 204) but modern scholars say between 100,000 to 150,000 Persians and 7,000 Greeks (Cassin-Scott).

Other Combatants & Casus Belli – chaoticblackcat

The Other Combatants

Due to its diverse empire, the Persian army varied in its makeup. According to Herodotus, who described the Persian army in great detail, it consisted of Persians, Medians, Cissians, Hyroanians, Assyrians, Bactrians, Sacians, Indians, Arians, Parthians, Chorasmins, Gandarians, Nadicaes, Casians, Sarangaes, Pactyes, Utians, Mycians, Parccanians, Arabians, Ethopians (specifically from the South of Egypt), Libyans, Paphlagonians, Matienans, Armenians, Phrygians, Lydians, Mysians, Thracians, Milyans, Moschians, Tibarenians, Macrones, Mossynoecians, Mares, Colchians, Alarodians, Sasperians, and islanders hailing from islands in the Red Sea (429-433). Herodotus specifically identifies the Median and Cissian contingents and the Persian Immortals as combatants that clashed with the Greeks in the Battle of Thermopylae (478). However, it must be noted that Cartledge makes the claim that most historians today would not believe “the accuracy of Herodotus’s reported figures of 1,700,000 Persian land troops and over 1,200 warships” (109). He speculates that the number was actually close to 80,000 troops and 600 warships and that the maximum description of the Persian army was done for maximum effect (110).

Herodotus describes the Greek army present at Thermopylae to be made up of an elite force of three hundred from Sparta, five hundred from Tegea, five hundred from Mantinea, one hundred and twenty from Orchomenus, and one thousand from other areas of Arcadia (475). There were also four hundred from Corinth, two hundred from Phleious, eighty from Mycenae, seven hundred from Thespiae, four hundred from Thebes, a thousand from Phocis, and every available man from Opuntian Locris (Herodotus 475). However, much like Cartledge’s earlier claim that Herodotus’s count of the Persian army was questionable, Michael A. Flower, a Classics Professor at Princeton University, has a similar question about Herodotus’ description of the Greek army.

In his article “Simonides, Ephorus, and Herodotus on the Battle of Thermopylae,” Flower analyzes the Greek sources referenced on the Battle of Thermopylae, such as Ephorus, Diodorus, Simonides, and Plutarch. He writes “that there are at least two features of Diodorus’ account which some modern scholars have accepted over Herodotus,” and one of them relates to the number of Lacedaemonians who fought at Thermopylae. (367). He writes that in one area of the text Herodotus mentions the famous 300 Spartans and “a total of 3,100 Peloponnesian hoplites,” but Herodotus later contradicts himself by quoting an epitaph which has a record of 4,000 men (367). He says that, based on what Diodorus wrote, it is likely that Herodotus forgot to include “700 Lacedaemonians because they did not stay to perish” in the final stand (368).

Now, in regards to the contingents and the notable roles they played in the Battle of Thermopylae, Herodotus describes a few specific contingents as having played specific roles in the battle. The Thebans and the Thespians are noted for staying behind with the Spartans in the final stand (Herodotus 482). Herodotus also explicitly gives the Phocians credit for guarding the “pass across the mountain” where Xerxes would ultimately break through (480). These groups are often overlooked during discussions of the Battle of Thermopylae, thrown into obscurity by the famed Spartan resistance. In some cases, they might be unfairly maligned.

Herodotus makes a point of noting that the Spartan leader Leonidas recruited the Thebans, led by their Theban commander Leontiadas, because “they were strongly suspected of collaborating with the enemy,” and the Spartan Leonidas was testing whether or not they would commit to the fight against the Persians (475-476). Herodotus claims that the Thebans “did send troops, but in fact their sympathies lay elsewhere” (476).  He also claims that they stayed primarily because they were essentially Leonidas’s captives and surrendered to Xerxes the first chance they got (482, 485).

This claim that the Thebans fighting at Thermopylae were unwilling combatants who had Persian loyalties is disputed by a few modern day scholars. In his article, Flower emphasizes that this is another place where modern scholars prefer the Greek historian Diodorus’ account over Herodotus’ version of events (367). Herodotus states that the Thebans were forced to fight by Leonidas whereas Diodorus indicates that the city of Thebes was overall undecided on where to stand, and the Thebans who fought at Thermopylae were amongst those who were against any alliance with the Persian Empire (Flower 371).

This theory is supported by a professor emeritus from the University of British Columbia’s Department of Classical, Near Eastern, and Religious Studies named J.A.S. Evans who writes that “for the Thespians and the Theban contingent, which belonged to the anti-Persian faction in Thebes, there was no future if the Persians forced the pass; they preferred to stay and fight” (236-237). This theory is supported by a map, acquired from Wikipedia’s article titled “The Battle of Thermopylae,” which shows the Xerxes invasion in red lines. Taking into account the position of the Battle of Thermopylae, one can see that Xerxes did indeed pass through the city of Thebes. For the Thebans fighting, it was the last stand between their city and the Persians.


(Image from Wikipedia’s Article “Battle of Thermopylae”)

The same was likely true for the Thespians, for their city Thespiae was located near Thebes and Plataea (which, according to the map, was the location for another land-based battle a year later). Both the Thespians and Thebans likely stayed behind at Thermopylae because they believed that defeat for them meant the potential loss of their respective cities to the Persian invaders.

Casus Belli

The ancient world’s attitude toward war was very different from what it is today. While now it is considered to be something negative, there was once a time where it was considered noble. Such was the mentality of the ancient Greeks. Paul Cartledge, the professor of Greek history at the University of Cambridge, asserts that war was ingrained into their culture, and military experience was even considered a requirement for Spartan and Athenian citizenship (2-3). However, Cartledge urges that it is important to remember that this attitude was not unique solely to the Greek of the ancient world. To try and capture the ancients’ mentality, Cartledge uses the description provided by Thucydides, a man he names  “Herodotus’s greatest successor as a historian” (90). Thucydides wrote “that there are three factors in ‘all interstate relations’  which contributed to the wars fought during that time” (Cartledge 90). These factors are “strategic concern for a state’s collective security; ideological-psychological concern for its status, reputation and honour; and the desire for economic advantage or profit” (Cartledge 90). The first two factors played a part in producing the war which the Battle of Thermopylae was a part of.

The ancient Greek and Persian spheres came into contact when a few Greek cities on the “Mediterranean margins of the Persian Empire” were conquered by Persia in 540 BCE (Cartledge 17). The Greek of 500 BCE (twenty years prior to the Battle of Thermopylae) were defined by independent “mutually hostile political” cities; the Persian Empire, by contrast, was “the fastest-growing empire in the entire history of the ancient East” (Cartledge 16-17). The conquered cities later revolted against Persia in 499 BCE with the help of the Greek city Athens  (Cartledge 17). This revolt threatened the Persian state’s “ideological-psychological concern for its status, reputation and honour” leading to their first attempt at invading Greece (Cartledge 90). This invasion prompted the Greek’s “strategic concern for a state’s collective security,” and this first attempt to invade Greece ended rather poorly with the Persian defeat at the Battle of Marathon (Cartledge 90, 6).

However, these sentiments remained strong and eventually led to the second Persian invasion of Greece, which the Battle of Thermopylae was a part of. When the Persian King died, the famed Greek historian Herodotus records that he was succeeded by his son Xerxes (405). According to Herodotus, a primary force behind the instigation of war was this new Persian Emperor who, egged on by his cousin Mardonius, called together a meeting of Persia’s leaders and supposedly gave the following speech:

“I intend to bridge the Hellespont and march an army through Europe and against Greece, so that I can make the Athenians pay for all that they have done to Persia and to my father…So on his behalf, and on the behalf of all Persians, I will not rest until I have captured Athens and put it to the touch…If we conquer them and their neighbors—the inhabitants of the land of Pelops of Phrygia—we will make Persian territory end only at the sky,…With your help I will sweep through the whole of Europe and make all lands into a single land” (406-407).

Tactics & Topography – berossusofbabylon

The topography of the Battle of Thermopylae is inextricably tied to the Lacedaemonian’s tactics and, therefore, will be discussed together. When the Greek cities of the greater Peloponnese caught wind of the Persian forces—which, according to Herodotus, numbered in the millions— marching across Europe, they elected to hold their enemy at a pass known to the locals as the “Hot Gates” (Herodotus 467, 470). Local lore held that the sulfurous springs near the pass marked the entrance into the underworld, hence the name, and as if to foreshadow the display of Greek heroism that was to transpire there, an alter dedicated to Heracles had already been erected at the pass (467). As the Greek infantry headed to Thermopylae, “…the fleet was to sail to Artemisium in Histiaeotis, so that each of the two forces would be close enough to learn of the other’s situation” (467).

Meanwhile, to the southeast, Xerxes commanded his vast army across Asia Minor to the eastern reaches of the Aegean, moving northward from Sardis to Ilium (famed city of Homer’s Hector and Priam), where he bridged the Hellespont to the north with nearly 650 penteconters and triremes—large maritime vessels rowed by vertical tiers of between 100-200 oarsmen apiece (419-421). These ships were lashed together and packed with dirt, creating a colossal, floating bridge by which Persian forces could cross the straight, along with their baggage trains, camp followers, yoke-animals, cavalry, and chariots (420-421). From there, Xerxes marched his armies across Thrace, heading west into Macedonia before turning south along the western edge of the Aegean into Thessaly, gathering forces along the way (see figure below). The mountainous terrain allowed for only one viable route for such a vast host: the coastal path leading through the pass of Thermopylae.


Xerxes route out of Ionia, circumnavigating the Aegean (“Battle of Thermopylae”).


The pass itself is situated between a sheer, inaccessible cliff face to the west and an inlet of the Aegean to the east. Between this narrow pass, the Lacedaemonian-led Greek forces bottlenecked the Persian contingents sent against them, blocking Xerxes’ warpath to Athens. Though the Persians outnumbered the Greeks by orders of magnitude, the Greek’s spears—especially those of the Spartans’—were longer (478), and the Lacedaemonians in particular were trained to fight from childhood, having been sent to the Agoge (antiquity’s answer to West Point) at around the age of seven. According to Herodotus, wave after wave of Persian soldiers failed to break the relatively small assemblage of Greek contingents. Herodotus recounts that “The Lacedaemonians fought a memorable battle; they made it quite clear that they were the experts, and that they were fighting against amateurs” (478). Many of the Persians who weren’t impaled at the end of a Spartan lance slipped off the path, falling into the sea to drown, making the topography as much of a weapon for the Greeks as their swords and spears. Another unique tactic employed by the Greeks was to feign retreat further into the pass, restricting the Persians’ maneuverability even further so as to more easily dispatch them before returning to the mouth of the pass.


David, Jacques-Louis. Leonidas at Thermopylae. Oil on canvas. Musee du Louvre, Paris.

However, despite the more advantageous position, better training, and more effective weaponry, the Greek forces failed to foresee the Persians discovering a relatively little-known path used by the region’s goatherds—a trail leading behind the Greeks’ position: The Anopaea (480). Of the possible accounts of how Xerxes discovered the trail, Herodotus favors that featuring the traitor Ephialtes of Trachis, who informs Xerxes of the mountain path. On the third day of the battle, Xerxes deployed his commander Hydarnes to lead Persian contingents along The Anopaea, ultimately flanking the Greek forces on all sides.

By this point, all but the Spartan, Thespian, and Thessalian-captive forces remained because, according to Herodotus’ preferred account, Leonidas ordered the other contingents to return home but refused to leave himself because a Delphic oracle had foreseen that either Lacedaemon would be obliterated by the Persians or that its king would die in battle; Leonidas favored the latter as it would preserve Sparta and win him renown in the process (481). Herodotus illustrates the end of the battle with the Lacedaemonians fighting with their swords when their spears had broken, with their knives when they had lost their swords, and with their hands and teeth when they had lost their knives (483). With Persians on all sides, however, valiant as the Spartans’ efforts may have been, they were inevitably overwhelmed.

Herodotus concludes his account of the Battle of Thermopylae with a story of Demaratus, former Lacedaemonian king exiled to Persia turned advisor to Xerxes, and the secret message he delivered to Sparta—inciting the meeting that led the Greeks to Thermopylae in the first place. The legend has it that Demaratus wrote Xerxes’ decision to invade Greece on the wooden base of a writing tablet, hid it behind wax onto which a decoy message was written, and sent the message back to Lacedaemon (488). According to Herodotus, it was Gorgo, Leonidas’ wife, who suspected there was a secret message behind the decoy, and after deciphering the warning, she passed it along to the other Greek cities, so they might prepare for the advancing sea of Persian soldiers.


  1. “Ancient Greek Warfare.” Wikipedia: The Free Encyclopedia. Wikimedia Foundation, Inc. 8 July 2016. Web. Accessed: 22 Sept. 2016.
  2. Άγνωστος – National Museums Scotland. “Second Persian Invasion of Greece.” Wikipedia: The Free Encyclopedia. Wikimedia Foundation, Inc. 21 Sept. 2016. Image from web. Accessed: 21 Sept. 2016.
  3. “Battle of Thermopylae.” Wikipedia: The Free Encyclopedia. Wikimedia Foundation, Inc. 21 Aug. 2007. Image from web. Accessed: 22 Sept. 2016.
  4. Cartledge, Paul. Thermopylae: The Battle that Changed the World. Print, p. 405-485, Overlook Press, Woodstock & New York.
  5. Cassin-Scott, Jack. The Greek and Persian Wars 500-323 B.C. Osprey, 1977.
  6. Evans, J.A.S. “The ‘Final Problem’ at Thermopylae”. Greek, Roman, & Byzantine Studies vol. 5, no. 4 (Dec. 1967): 231-236. Stewart Library OneSearch. Web. 20 Sept. 2016.
  7. Flower, Michael A. “Simonides, Ephorus, and Herodotus on the Battle of Thermopylae”. The Classical Quarterly vol. 48, no. 2 (1998): 365-379. JSTOR. Web. 21 Sept. 2016.
  8. “Greco-Persian Wars.” Wikipedia: The Free Encyclopedia. Wikimedia Foundation, Inc. 21 Sept. 2016. Web. Accessed: 22 Sept. 2016.
  9. Happolati. “Immortals (Persian Empire).” Wikipedia: The Free Encyclopedia. Wikimedia Foundation, Inc. 6 Sept. 2016. Photograph from web. Accessed: 21 Sept. 2016.
  10. Herodotus.  The HistoriesTranslated by: Waterfield, Robin. Oxford University Press Inc. 1998: New York, NY.
  11. May, Elmer; Stadler, Gerald; Votaw, John; Griess, Thomas. “Classical Warfare: The Age of the Greek Hoplite.” Ancient and Medieval Warfare: The History of the Strategies, Tactics, and Leadership of Classical Warfare. 1984. New Jersey: Avery Publishing Group. Web. 21 Sept. 2016.
  12. Sacks, Kenneth. “Herodotus and the Dating of the Battle of Thermopylae.” The Classical Quarterly vol. 26, no. 2 (1976): 232-248. JSTOR. Web. 21 Sept. 2016.

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