For centuries, Sparta was ruled by two hereditary kings at once. They came from separate families, the Agiads and the Eurypontids, and both could command Spartan armies. Each held a kingship in his own right. Neither was merely the other’s deputy, and neither exercised sole authority over the city.
This was an unusual arrangement in the Greek world. Athens had dispensed with hereditary monarchy, and many other city-states entrusted government to councils or magistrates. Sparta retained two royal houses while allowing other institutions to scrutinise the kings, oppose them and sometimes depose them. Their hereditary office survived for hundreds of years within that wider political system.
The origins of Sparta’s two thrones are uncertain. Spartans explained them through twin descendants of Heracles, although the institution is easier to trace in practice than at its foundation. The evidence records the sharing of military and religious duties, competition between kings and the collapse of two independent dynasties in the third century BC.
Why Did Sparta Have Two Kings? The Story of the Twins
Herodotus, writing in the fifth century BC, traces both houses to Aristodemus, whom Spartan tradition counted among the descendants of Heracles. Aristodemus was said to have arrived in Laconia, the region of southern Greece around Sparta, with those who supposedly returned to the Peloponnese under Heracles’ descendants. His wife Argeia bore identical twin sons, Eurysthenes and Procles. Soon afterwards Aristodemus died, leaving two possible successors.
According to the story, the Spartans wanted the firstborn son as king but could not tell the twins apart. Argeia knew which was older and kept the answer to herself, hoping to secure kingship for both. Apollo’s oracle at Delphi prescribed a different solution: recognise both brothers, but honour the elder more highly. A Messenian adviser proposed observing which baby Argeia washed and fed first. The Spartans followed his advice and identified Eurysthenes as the elder brother.
The resulting dynasties had equal hereditary claims to a throne, though Spartan tradition ranked them differently. Eurysthenes’ descendants became the senior Agiads, named after his son Agis. Procles’ descendants became the Eurypontids, named after a later ruler, Eurypon. Herodotus recounts the succession story in Histories 6.52. Pausanias, a later Greek writer, also describes the twins but gives another account of Aristodemus’ death. These differing accounts leave the founding story as a tradition whose date and historical basis cannot be established.
Both families used their supposed descent from Heracles, and through him Zeus, to justify their right to rule. The Agiads claimed precedence, while the Eurypontids had a hereditary kingship of their own. No dependable evidence identifies an actual pair of newborn founders or establishes the date of the institution’s creation. The ancient king lists extend far into the Greek past, but the chronology assigned to their earliest rulers is not secure.
Sparta grew from settlements in the Eurotas valley during the early Iron Age. Historians have suggested that two prominent communities or groups may have kept their respective leaders as a single city-state developed. Such a merger might account for two royal houses, but neither archaeology nor inscriptions confirm that it happened. Archaic poetry and later accounts of Spartan law provide firmer evidence that the institution existed. Work on the seventh-century poet Tyrtaeus also suggests that stories of Heracles’ descendants returning to the Peloponnese helped defend royal legitimacy during political struggles. They need not reflect a continuous, peaceful succession from a legendary beginning.
What Powers Did the Two Spartan Kings Have?
Each Spartan king was at once a hereditary military leader, priest and member of the governing council. Both dynasties held broadly the same powers. There was no fixed division in which one family commanded troops and the other oversaw religion. Individual standing, circumstances and the willingness of other Spartans to cooperate could make one king far more influential than his colleague.
Command in war was the most conspicuous royal responsibility. A king on campaign oversaw the march, army formations and military decisions, travelling with an armed guard and specialists who performed the required sacrifices. In Histories 6.56–57, Herodotus describes both the right to conduct expeditions and the honours attached to that role. These rights did not remain identical throughout Spartan history. A king might exercise considerable discretion in the field yet still lack the power to start every war or determine policy at home by himself.
The kings’ religious position was just as firmly established. Each held priesthoods of Zeus Lacedaemonius and Zeus Ouranios, two cult titles of Zeus, performed public sacrifices and safeguarded oracles delivered to Sparta. Each also appointed two Pythioi, officials who consulted Apollo’s oracle at Delphi. Sacrifices mattered on campaign: an unfavourable result could postpone a march or battle, bringing royal priesthood directly into military command.
Herodotus lists a range of more specific privileges. Kings enjoyed honoured places at festivals and received double portions at communal meals. Their judicial functions extended to certain questions involving an unmarried heiress whose father had made no marriage arrangement, and to disputes over public roads. Adoptions took place in their presence. They could also appoint proxenoi, citizens who represented foreigners’ interests in Sparta. These were defined privileges and responsibilities. Neither king judged every lawsuit or controlled the economy.
Public resources supplied the royal households with provisions and animals for sacrifice. A king’s death brought an exceptional public mourning ceremony. Herodotus describes the news spreading through Laconia, compulsory mourning among people of different legal ranks, and a suspension of normal civic business for ten days. The funeral honours distinguished a king from other citizens. During his lifetime, however, even that honoured figure remained subject to the city’s political institutions.
Who Controlled the Kings? The Gerousia, Ephors and Assembly
Several governing bodies shared power at Sparta. The gerousia, its council of elders, comprised twenty-eight men over sixty chosen for life, together with the two kings. The council prepared matters for the citizen assembly and handled important judicial business. Each king therefore sat as one member of a thirty-person council; he could not simply issue orders to it. The assembly, usually called the apella, consisted of male citizens with full political rights and voted on the proposals placed before it.
Sparta also selected five ephors, or overseers, each year. They managed much of the administration, dealt with visiting envoys, supervised public affairs and could call royal conduct into question. Their responsibilities developed over time, and the extent of their powers in every period is uncertain. Hereditary kings could therefore be held accountable by magistrates who belonged to neither royal family. In the fourth century BC, Aristotle criticised both the strength of the ephors and the selection of elders in his discussion of the Spartan constitution in Politics, Book II.
Xenophon, a writer familiar with Sparta, records how the relationship was renewed through a monthly exchange of oaths. The kings promised to govern according to the established laws. The ephors, speaking on behalf of the city, promised to uphold the kingship as long as that undertaking was honoured. Heredity secured the office, but lawful conduct was a condition of the city’s support. Xenophon describes the ceremony in Xenophon’s Constitution of the Lacedaemonians, chapter 15.
These formal checks did not always determine a king’s influence. Royal influence also depended on allies, religious authority and success in war, which individual kings could use to gain political support. The evidence shows that the other institutions did not restrain every king equally, or with the same effectiveness in every period. Ellen Millender’s research on Spartan kingship and royal prerogatives emphasises how differently royal prerogatives could operate depending on the person who held them.
The political community involved was small. Membership in the assembly was restricted to Spartan men with full citizenship, excluding most inhabitants of Laconia and Messenia. The perioikoi, free communities around Sparta, had no equivalent voice in the assembly. Helots were an unfree population obliged to work land controlled by Spartan households and possessed fewer rights still. Constraints on the two kings coexisted with harsh control over the populations on whose labour Sparta depended.
Why Did Only One King Usually Lead an Army?
Early Spartan armies could be accompanied by both kings. Herodotus connects the abandonment of that practice to a failed expedition around 506 BC. Cleomenes I, an Agiad, advanced against Athens with Spartan troops and allies while the city was caught in a political struggle. Demaratus, his Eurypontid colleague, joined the campaign. At Eleusis the Corinthians pulled out, and Demaratus also withdrew. Their departure caused the expedition to unravel before the expected battle.
As Herodotus 5.75 explains, Sparta subsequently barred the kings from going on the same expedition together. One stayed behind while the other marched. The prohibition extended to the divine twins Castor and Polydeuces, the Dioscuri, whose sacred images or presence had accompanied the army. The incident had made an immediate problem clear: two equal commanders could disagree in front of their allies and bring a campaign to a halt.
A king remaining in Sparta had useful responsibilities. The state held territory beyond the city, ruled over subject communities and feared helot rebellion, particularly in Messenia. A royal leader could remain available while the army was abroad. Yet the arrangement was no universal rule of one permanent home defender and one campaigning king. A ruler might be exiled, absent, too young or politically sidelined. Sparta also entrusted armies to commanders who did not hold either throne.
Military commands during the Persian Wars illustrate this flexibility. Leonidas I, an Agiad, led the Greek defence at Thermopylae in 480 BC and was killed there. In 479 BC Leotychidas II, the Eurypontid king, commanded the Greek fleet at Mycale. The victorious land force at Plataea, however, was led by Pausanias, serving as regent for the young Agiad Pleistarchus. Pausanias was not a reigning king. Regents and appointed generals could lead armies even when neither was a reigning king.
Exile could leave one royal house without an active king for years. During the Peloponnesian War between Sparta and Athens, beginning in 431 BC, the Eurypontid Archidamus II led Spartan forces into Attica. Pleistoanax, the Agiad king, was then in exile and did not return until 426 BC. For those years Sparta did not have two active royal commanders dividing responsibilities at home and abroad. The thrones survived disputes that could remove their occupants from public life.
Agiads and Eurypontids: Two Families, Different Fortunes
Succession normally passed from a king to his son within each house. Trouble arose if the accepted heir was missing, his parentage was challenged or the king left no acknowledged son. A brother or another male relative might then claim the position. Brenda Griffith-Williams examines the rules and procedures applied in disputed cases in her study of Spartan royal succession from 520 to 400 BC.
Cleomenes I’s conflict with Demaratus reached into the succession itself. Following the failed campaign at Eleusis, Cleomenes challenged his fellow king’s legitimacy. Herodotus says the charges concerned Demaratus’ birth and that a response from Delphi was manipulated. Demaratus was deprived of the Eurypontid kingship around 491 BC and replaced by Leotychidas II. Separate hereditary titles could become weapons in the struggle between their holders.
The career of Agesilaus II shows how a Eurypontid king could dominate Spartan politics despite the Agiads’ traditional precedence. He took the throne around 400 BC after a contested succession and campaigned in Asia Minor against Persian forces. During the fourth century BC he became one of Sparta’s dominant political figures. Among the Agiad kings serving alongside him were Pausanias and later Agesipolis I. Agesilaus belonged to the Eurypontid house, sometimes treated as the junior dynasty. His prominence therefore illustrates the changing balance of influence between the two houses.
The two houses produced leaders with sharply different careers. Leonidas and Cleomenes I were Agiads; Archidamus II, Agis II and Agesilaus II were Eurypontids. Individual careers, rather than a permanent division of military command or foreign policy, explain their different reputations and ambitions. Each family possessed a continuing claim to royal office within a state where influence had to be contested.
Religion, Heracles and the Divine Twins
Spartans also honoured another famous pair of brothers. Castor and Polydeuces, collectively called the Dioscuri, were important religious figures in Laconia. Greek myth made them sons of Leda and associated them with horses, rescue and shared honours. They offered a familiar religious image of twinship for a city governed by two kings with parallel sacred roles. Herodotus’ story of the Eleusis campaign makes the connection tangible, since the Dioscuri’s sacred presence accompanied the royal army before the custom changed.
The connection did not make Castor and Polydeuces the dynastic ancestors of Sparta’s kings. The two royal genealogies instead ran through Heracles, son of Zeus. In his 2011 study of Spartan dual kingship, anthropologist Marshall Sahlins interpreted the double kingship through a broader religious pattern of sovereign twins. He proposed a way of understanding how Spartans could regard two kings as sacred rulers. It cannot establish when, or under what historical circumstances, their royal institution was founded.
Royal funeral rites gave kings exceptional standing, even as their successors remained accountable to the city. A dead king received public honours greater than those due to an ordinary citizen. His successor, whatever his sacred standing, was expected to obey Spartan law and deal with magistrates. Religious prestige helped preserve the monarchy, while the city’s institutions kept that prestige from automatically becoming unrestricted power.
How Did Sparta’s Dual Kingship End?
By the third century BC the conditions that had sustained Sparta’s military and political supremacy had deteriorated. Its defeat at Leuctra in 371 BC was followed by the loss of Messenia, a severe blow to regional power. Land and citizenship had become concentrated among fewer people, leaving too small a citizen body to support the old military organisation. Both dynasties still existed, but the constitutional structure surrounding them was under growing strain.
Agis IV, who became Eurypontid king in the 240s BC, sought to increase the citizen population through the cancellation of debts and redistribution of land. Leonidas II, the Agiad king, opposed him. Agis’ supporters briefly controlled the ephorate and cancelled debts, but the intended land reform stalled. When his opponents regained power, Agis was arrested and executed in 241 BC. Plutarch’s Life of Agis, chapters 19–21 describes the deaths of Agis, his mother and his grandmother. Plutarch wrote centuries after the events, so his narrative requires caution.
Cleomenes III, an Agiad and son of Leonidas II, later tried to reshape the state through force. In 227 BC he sent loyal soldiers against the ephors: four were killed and the fifth escaped. Cleomenes abolished the office and pursued reforms of landholding, debt and military organisation. With troops under his command, Cleomenes could overturn the ephors’ authority and remove a central restraint on kingship. The attack is narrated in Plutarch’s Life of Cleomenes, chapter 8.
Cleomenes then installed his brother Eucleidas as king on the throne traditionally reserved for a Eurypontid. Both brothers were Agiads, leaving two kings on the thrones but ending the rule of separate Agiad and Eurypontid houses. Archidamus V, the previous Eurypontid king, had been killed following his return from exile, and ancient accounts dispute Cleomenes’ involvement. The 2023 Historical Review of Sparta, published by Sapienza University Press, discusses those events and the disagreements between the surviving accounts.
In 222 BC the brothers were defeated at Sellasia by an army led by Antigonus III Doson, king of Macedon, with support from the Achaean League. Eucleidas died in battle; Cleomenes escaped to Egypt. Sparta subsequently saw attempts to restore monarchy, sometimes under rulers whose dynastic legitimacy was disputed. The stable pairing of Agiad and Eurypontid houses was not re-established. By the early second century BC, men such as Nabis ruled in circumstances unlike the classical dual kingship.
Why Did the System Survive for Centuries?
The origin story gave the two dynasties a shared ancestry, and succession within each family allowed Sparta to replace a king without abandoning kingship. Command in war and the conduct of public sacrifices kept the office useful long after hereditary monarchy had disappeared in many other Greek cities. The gerousia, ephors and citizen assembly retained ways to restrain royal power, although their effectiveness depended on the political circumstances.
The arrangement did not prevent individual kings from abusing their position. Cleomenes I helped remove Demaratus; much later Cleomenes III seized control of the ephorate and put his own brother on the second throne. The institution lasted because it occupied a recognised place in Spartan religion, army leadership and civic life. Its practical stability rested on political bodies able to keep ambitious rulers within accepted limits.
For centuries, Spartan monarchy endured alongside the council, annually elected ephors and citizen assembly. The two dynasties could endure rivalry and the removal of individual kings because the wider political order still had authority. Once that order began to break apart in the third century BC, the presence of two thrones offered little protection.
