Were there any wars in ancient Greece where religion played a major part?

Question

I know that the Greeks had a god of war and many other deities associated with warfare in some respect. I also know that the Greeks would consult the oracles for advice prior to their military endeavours. But what i am unsure of is whether there where any conflicts in the ancient Greek world which resembled closely the crusades of medieval times in terms of ideology and propaganda?

The only example i know of the top of my head is Alexander the Great's war against the Persians where he "exacted revenge" for their burning of the Greek temples:

"He also set the Persian palace on fire against the advice of Parmenion, who argued that it was ignoble to destroy what was now his own property and that the peoples of Asia would not pay heed to him in the same way if they assumed he had no intention of governing Asia but would merely conquer and move on. [12]But Alexander declared that he wanted to pay back the Persians, who, when they invaded Greece, had razed Athens and burned the temples, and to exact retribution for all the other wrongs they had committed against the Greeks. It seems to me, however, that in doing this Alexander was not acting sensibly, nor do I think there could be any punishment for Persians of a bygone era."

-Arrian: 3.18.11-12

Answer 1

Certainly. In fact there was even a whole series of Sacred Wars.

More specifically, the First Sacred War was fought by the Amphictyonic League against the city of Cirrha over the latter's mistreatment of religious pilgrims to Delphi. Delphi derived religious significance from its Temple of Apollo, which housed the famous Pythia - the Oracle of Delphi.

The Amphictyonic League was an ancient religious organisation which formed to support the temples of Apollo and Demeter at Delphi and Anthele.

The Amphictyons (literally, “dwellers around”), or Amphictyonic League, oversaw the oracle of Apollo at Delphi and had the power to declare wars (called Sacred Wars) against those guilty of sacrilege.

_{- Phillips, David D. Athenian Political Oratory: 16 Key Speeches. Psychology Press, 2004.}

Pilgrims from all over Greece came to Delphi to seek answers from the priestess, the most prestigious of her kind in the classical world. Many of them would disembark at Cirrha, the closest port to Delphi. The city took advantage of this to impose a toll on pilgrims, a sacrilegious act that ultimately provoked a war with the Amphictyonic League.

Delphi was situated at the foot of Mount Parnassus, and visitors to the shrine who came from any part of Greece by sea usually landed at Cirrha, a seaport town on the north shore of the Gulf of Corinth, which happened to be the nearest port to the oracles ... The men of Cirrha were in the habit of extorting heavy dues from travellers on their way to Delphi, and as they would not abandon their exactions at the order of the Amphictyons, these representatives of the Greek states ordered war to be undertaken against them.

_{- Robinson, John. Ancient History: A Synopsis of the Rise, Progress, Decline and Fall of the States and Nations of Antiquity. London, 1821.}

Not only did the war began with a distinctively religious cause, it also ended on a religious note as the lands of Cirrha were made sacred.

The First Sacred War was subsequently fought, resulting in the destruction of Cirrha. The plain around Cirrha was then dedicated to Delphi and cultivation of the land was forbidden.

_{- Ashley, James R. The Macedonian Empire: the Era of Warfare Under Philip II and Alexander the Great, 359-323 BC. McFarland, 2004.}

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This affair is actually somewhat similar to the later Crusades of Christendom:

The Amphictyonic league at length - under pressure, it is said, from Solon - proclaimed a kind of holy war against the Cirrhaeans, something like the crusade undertaken to free Christian pilgrims from the tax levied by the Saracens at the gates of Jerusalem.

_{- Shuckburgh, Evelyn S. A Short History of the Greeks: From the Earliest Times to BC 146. Cambridge University Press, 2013.}

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As @Matt pointed out in the comments, so-called religious wars in history were almost always also motivated by economical and political concerns. The First Sacred War is no exception here.

Answer 2

Although I can see why Ricky’s answer has been downvoted, I think he is actually making one perfectly valid point. The point is that religious warfare today has the meaning of a clash between people of different religious dogmata. The “Sacred Wars” of the Greeks were nothing of the sort, as the combatants were not divided by religious belief. In the case of the Greeks the term “Sacred Wars” simply denotes that the opponents fought over the control of a sacred sight (the Delphic Oracle). The Greek Sacred Wars were not about doctrine. In this sense, Ricky is right in pointing out that it was not religious doctrine that motivated warfare before the advent of Christianity.

Answer 3

No. Burning of temples is pretty much "sticking it to their gods," and avenging it is "sticking it to theirs."

The idea of sacrificing one's life for one's faith was originally a Hebrew thing, later picked up by Christians, and later still by Muslims.

Judeo-Roman wars weren't strictly religious wars: Rome disputed, not the Jews' right to worship God, but rather some of the Jewish laws that came with it that had a bearing on Roman jurisprudence.

The first true religious wars were the Crusades, the idea being to reclaim places sacred to all Christians from the Muslims, who by then also regarded many of those places as sacred. The minor clashes between the Catholics and Orthodox Christians came later.

The concept of religious faith as we know it is an intrinsically monotheist concept. That is why pagans have neither saints nor martyrs.