Hello!
In our last lesson, we set the stage for the Peloponnesian War by examining the initial grand strategies of the two great powers. You'll recall Sparta's land-based strategy of annihilation—the "Archidamian Strategy"—aimed at forcing a single, decisive battle by ravaging Attica. In contrast, Athens, under Pericles, adopted a radical strategy of exhaustion, planning to use its walls and navy to outlast and wear down the Spartan alliance.
Today, we'll see how those plans collided with the brutal realities of war. This lesson will describe the major events of the Archidamian War, the first ten-year phase of the conflict (431-421 BC). We will follow the story from the first invasions and an unforeseen catastrophe, through surprise victories and brilliant counter-moves, to the exhausted stalemate that brought this chapter to a close.
The War Begins: Strategy vs. Reality (431-429 BC)
As planned, in the summer of 431 BC, the Spartan King Archidamus led the Peloponnesian army into Attica. True to Pericles's strategy, the Athenians abandoned their farms and withdrew behind the Long Walls, turning their city into a crowded, fortified island. While the Spartans burned the countryside, the Athenian navy launched raids along the Peloponnesian coast.
For the first year, the strategy worked. Athens was inconvenienced but not seriously harmed, while its naval raids demonstrated its reach. However, in 430 BC, Pericles's carefully calculated plan was shattered by an enemy no one had anticipated.
The Delian League, Part 4: The Ten Years War (431/0-421 BCE)
The following article from World History Encyclopedia provides a clear, year-by-year narrative of the war. We'll use it to trace the major events chronologically.
Please read the sections 'FIRST YEAR OF WAR: 431/30 BCE' and 'SECOND YEAR OF WAR: 430/29 BCE', including the sub-section on 'THE GREAT ATHENIAN PLAGUE'. Focus on how the war played out in the first two years and the devastating impact of the plague.
The plague was a random, catastrophic event that no strategy could account for. It thrived in the overcrowded conditions Pericles's own strategy had created. Thucydides, who survived it himself, gives a harrowing account of the breakdown of law and religion as the city was consumed by death.
Strategically, the consequences were immense:
- Massive Casualties: Athens lost perhaps a third of its population, including thousands of trained soldiers and sailors. This crippled the manpower base that its imperial strategy depended on.
- Leadership Vacuum: The most significant victim was Pericles himself, who died in 429 BC. His death removed the one leader with the authority and vision to maintain the difficult, defensive strategy.
Athens After Pericles: A More Aggressive War (428-425 BC)
With Pericles gone, Athenian politics became more volatile. A new type of leader, often labeled "demagogues" by aristocratic writers like Thucydides, came to prominence. The most notable was Cleon, a tanner by trade, who advocated for a more ruthless and aggressive prosecution of the war. This shift in attitude was demonstrated starkly in the revolt of Mytilene on the island of Lesbos.
The Delian League, Part 4: The Ten Years War (431/0-421 BCE)
Let's return to the World History Encyclopedia article to see how Athens responded to its first major internal challenge of the war.
Please read the section for the 'FOURTH YEAR OF WAR: 428/7 BCE'. Note the initial brutal decree against Mytilene, pushed by Cleon, and how it was narrowly reversed. This event is a classic case study in Athenian democratic debate and their changing imperial mindset.
The Mytilenean Debate showed a city grappling with its own identity. While compassion narrowly won out, the incident revealed a willingness to use terror to maintain the empire, a far cry from Pericles's more measured approach.
This new aggression, combined with military innovation, soon led to Athens's greatest success of the war. The key figures were Cleon, the politician, and Demosthenes, an innovative general who was learning to combine different troop types and tactics—a departure from traditional hoplite warfare.
The following video masterfully explains this new Athenian offensive and its stunning climax.
Geostrategy of the Peloponnesian War 3: The Archidamian War
The 'Strategy Stuff' channel provides excellent military analysis. This video explains the shift in Athenian strategy under Cleon and the masterful operation conceived by Demosthenes.
Please watch the segment 'II. Athens: Cleon’s Strategic Offensive' (from 06:32 to 11:31). Pay close attention to how Demosthenes' new tactical 'package' (using light troops, unconventional tactics) was used to achieve a stunning victory at Pylos and Sphacteria.
The capture of 120 elite Spartan citizens (Spartiates) at Sphacteria in 425 BC sent shockwaves through the Greek world. Sparta, whose entire society was built on the myth of the invincible warrior who never surrenders, was utterly humiliated. More importantly, Athens now held hostages that forced Sparta to stop its annual invasions of Attica. For a moment, it seemed Athens was on the verge of total victory.
Test your understanding!
The capture of a few hundred soldiers might not seem decisive in a large war. Why was the capture of just 120 Spartiates at Sphacteria such a devastating strategic blow to Sparta?
Show answer
It was devastating for two main reasons. First, it shattered Sparta's aura of invincibility. The psychological impact on allies and enemies was immense. Second, and more critically, Sparta faced a severe demographic crisis. The number of full Spartan citizens (Spartiates) was incredibly small, possibly only a few thousand at this time. Losing 120 of them, along with nearly 300 other Peloponnesian troops, was a demographic catastrophe they could not easily replace. Each Spartiate represented a significant portion of their elite military and political class.
The Spartan Counter-Punch: Brasidas in the North (424-422 BC)
Reeling from the disaster at Sphacteria and unable to invade Attica, Sparta was strategically paralyzed. In a move born of desperation, they sanctioned a high-risk, high-reward mission led by their most brilliant and unconventional general, Brasidas.
His plan was to march an army of non-citizen troops (helots and mercenaries) the length of Greece and attack Athens's possessions in the north, particularly in Thrace. This region was vital to Athens for its tribute, timber for ships, and, most importantly, its silver mines.
The Strategy of the Peloponnesian War
Let's turn back to our first 'Strategy Stuff' video, which provides a concise overview of Brasidas's campaign and its impact.
Watch the segment from 06:26 to 09:21. Notice how Brasidas's success wasn't just military; he was a masterful diplomat, presenting himself as a 'liberator' of Greeks from Athenian tyranny. This part of the video also covers the key Athenian setbacks at Delium and the capture of the crucial city of Amphipolis.
Brasidas's campaign was a spectacular success. He captured the vital city of Amphipolis—a failure for which the historian Thucydides, who was the Athenian general in the area, was exiled. By striking at the source of Athens's wealth, Brasidas had found a way to hurt Athens without engaging its navy.
The End of the Beginning: A Bloody Peace (422-421 BC)
The war had now reached a fever pitch. In Athens, Cleon, buoyed by his success at Sphacteria, led a force to the north to reclaim Amphipolis and deal with Brasidas. The two leading war hawks of Athens and Sparta finally met in battle in 422 BC.
In the ensuing Battle of Amphipolis, both Cleon and Brasidas were killed.
With the most aggressive proponents of the war dead on both sides, the path to negotiation was finally open. Both city-states were exhausted. Athens was shaken by the loss of its northern territories, and Sparta was desperate to recover the hostages from Sphacteria. In 421 BC, they agreed to the Peace of Nicias, named after the cautious Athenian general who brokered it. The treaty was supposed to last for 50 years and essentially returned things to the pre-war status quo.
The Archidamian War was over. It ended not with a decisive victory, but with a weary, bloody, and deeply unstable truce.
Conclusion
In this lesson, we have traced the arc of the first decade of the Peloponnesian War. We saw how well-laid plans were thrown into chaos by chance, how leadership changes altered the course of the conflict, and how military innovation led to dramatic reversals of fortune.
Key Takeaways:
- The initial phase of the war was defined by Spartan invasions of Attica and Athenian naval raids.
- The Plague of Athens (430-427 BC) was a turning point, devastating Athens's population and leading to the death of Pericles.
- After Pericles, Athens adopted a more aggressive strategy under leaders like Cleon, culminating in the stunning victory at Pylos and Sphacteria (425 BC), where hundreds of Spartan soldiers were captured.
- Sparta responded with a brilliant counter-attack led by Brasidas, who successfully instigated revolts among Athens's allies in the north, capturing the key city of Amphipolis.
- The war's first phase ended after both Cleon and Brasidas were killed in battle, leading to the exhausted and fragile Peace of Nicias in 421 BC.
Preview of the Next Lesson:
The Peace of Nicias was a peace in name only. It failed to address the deep-seated rivalries that started the war, and many key allies on both sides refused to accept its terms. In our next lesson, we will explore the failures of this peace, analyze the significance of the Peace of Nicias as a temporary halt in the conflict, and meet the charismatic and treacherous figure of Alcibiades, whose ambition would soon lead Athens to its greatest gamble and its most catastrophic disaster.