When & Why Did Sparta Ally with Persia – The Truth

One of the first things we connect to Sparta is the Battle of Thermopylae and the Spartan resistance against the Persian invasion of Greece. But it might come as a surprise to you that after the Greco-Persian Wars were over, the enmity between Sparta and the Persian Empire didn`t last very long. And Sparta even accepted Persian help to win the Peloponnesian War against Athens (Sparta’s ally during the Persian Wars).

But why did the Persian Empire help Sparta against Athens? And what did the Persian help for Sparta look like?

The last phase of the Peloponnesian War (the Decelean War from 414 to 404 BC) was mostly shaped by naval battles in the northern and eastern Aegean Sea. Sparta’s need for a strong navy and the Persian interest in breaking the Athenian dominance in the Aegean Sea caused the two powers to team up against Athens. So since 412 BC the Persians financed Sparta so that Sparta could build a strong navy and defeat Athens in 404 BC.

Thanks to the Persian money Sparta actually managed to defeat Athens in 404 BC. But that victory came at a cost. In order to get financial help, Sparta make concessions to the Persian Empire that eroded Sparta’s reputation among the other Greek city-states and eventually contributed to Sparta’s downfall.

But that is another story. Let`s now take a closer look at the Persian help for Sparta during the Peloponnesian War.

Why Did the Persian Empire Help Sparta Against Athens?

Let`s start out with a small recap of the situation in 414 BC, the year before the Persian Empire started to aid Sparta.

The Peloponnesian War was shaped by an alternation between phases of high intensity and phases of lower intensity. In 414 BC, one of these phases of lower intensity ended, and the Peloponnesian War that had gone on since 431 BC went into its last, deciding, phase.

The last phase of the Peloponnesian War, the so-called Decelean War waged between 414 and 404 BC, was shaped by naval battles in the eastern and northern Aegean Sea. And while Sparta had always had its own fleet the Athenian fleet was superior in both numbers and quality.

So in 414 BC Sparta needed a stronger fleet!

But that was not the only new development in 414 BC. Simultaneously with the reignition of the Peloponnesian War, an old enemy of Athens reentered the picture.

Athens had been engaged in its Sicilian expedition since 415 BC and in 414 BC it already showed that things were going bad for Athens (the Sicilian expedition would end in a total disaster for Athens in the late fall of 413 BC). The weakness of Athens that was the result of the disastrous Sicilian expedition encouraged the Persians to try and break the Athenian dominion in the Aegean Sea and extend the Persian influence.

Now it might seem like the Persian interest in weakening Athens came from nothing. But there was a trigger for the Persian actions. Athens had supported a Persian governor in Asia Minor in his attempt of breaking away from the Persian king in 414 BC which ended the peace treaty that had been closed between Athens and the Persian Empire in 449 BC. By assisting the rebellion of a Persian governor in 414 BC, Athens broke the peace treaty between Athens and the Persian Empire from 449 BC and caused the Persians to interfere in Greece. And not even 100 years before, Athens had already supported another rebellion, this time of Greek city-states, against the Persian king, which caused the Greco-Persian Wars.

Isn`t it interesting how history repeats itself?

So once again the Persians were willing to interfere in Greece to improve their own political position after Athens had broken their peace treaty from 449 BC.

But this time the Persians didn`t plan an invasion since the two big alliances, the Peloponnesian League (led by Sparta) and the Delian League (led by Athens), were already working hard towards weakening each other. This time the Persians simply had to finance the war against Athens to hurt its old enemy and improve the Persian position.

The first agreement between Sparta and the Persian Empire was made in 412 BC. Sparta would leave Asia Minor (including the Greek city-states in Asia Minor) to the Persians and the Persian Empire would give Sparta a loan so that Sparta could strengthen its navy.

By the way. The fact that Sparta, that just like Athens drew its claim of dominion over the other Greek city-states from its role in the Persian wars, bargained away Greek citystates for Persian money was one of the 3 reasons that led to the downfall of Sparta!

Sparta was able to drastically increase the size of its navy and was able to deploy a huge fleet into the Aegean Sea in 412 BC. With the help of its new fleet, Sparta was able to take several strategically important positions at straits away from Athens and even managed to convince two important Athenian allies, Milet and Rhodos, to flip.

But even though these losses were devastating to Athens, they didn`t end the Peloponnesian War. But a new development would push Athens to its breaking point (and gives us a good opportunity to look at what the Persian help for Sparta looked like).

How Did the Persian Empire Help Sparta Against Athens?

As mentioned, the Persians were sending Sparta money ever since 412 BC. But until 407 BC the money did not come from the Persian king of kings himself but from the Persian satrap (governor) Tissaphernes of Lydia and Ionia.

But that changed in 407 BC.

In 407 BC the Persian king Darius II installed his 16-year-old son Kyros as satrap (governor) of Lydia, Phrygia, and Cappadocia and also named him military commander over all the troops stationed in these provinces.

In 408 BC a Spartan legation had arrived at the court of the Persian king of kings Darius II and asked the Persians for more financial assistance for the war against Persia. So in the spring of 407 BC, the Persian prince Kyros sent 500 talents (28,660 lbs / 13000 kg) of silver to Sparta so that Sparta could once more increase its fleet. In return, Sparta left all Greek citystates in Asia Minor to the Persians although it was agreed upon that the Greek citystates would have to pay tributes to the Persians but would not be integrated into the Persian satrapy system. So they would remain autonomous, at least on paper.

Even with the Persian money the Peloponnesian war would still continue until 404 BC before the Spartan fleet could force Athens into a total defeat. Do you want to find out why the Peloponnesian War lasted so long (from 431 to 404 BC)? Then I would like to recommend you my article here.

However, the decision to leave Greeks and Greek citystates to the Persians would hurt Sparta’s reputation after its victory over Athens in 404 BC and would contribute to the downfall of Sparta.

The Persian Empire had also reached its goal. By allying with Sparta and financing the Spartan war efforts against Athens, the Persian Empire had gained control over the Greek citystates of Asia Minor and had successfully reintroduced itself into the politics of Greece.

However, not even 75 years later the Persian Empire would also succumb to war and a young Macedonian king, Alexander the Great, would take control over the empire. Now some think that Alexander invaded the Persian Empire simply because he wanted to. But that is actually pretty far away from the truth. Alexander the Great had no other option than to continue the war against the Persian Empire since he had inherited the war from his father.

But that is a story for another time.

Take care of yourself because you deserve it. You really do.

Until next time

Yours truly

Luke Reitzer


Karl-Wilhelm Welweit: Sparta. Aufstieg und Niedergang einer antiken Großmacht (Stuttgart 2004).* 

Plutarch: On Sparta.*

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