There is much discussion over whether it was Greek unity that caused the victory against the Persians in the years 490BC-479BC. The three main points of view on the matter is that they were not united at all, which can be seen from the accounts of Herodotus, that they were united, which can be seen in the Themistocles Decree and that it was Themistocles himself that made them unified.
It is on the research of Herodotus that we rely most heavily on for our information of the Persian War period. He is often criticised for his inaccuracy, bias and failure to evaluate events properly. Unfortunately there is no other major ancient source against which scholars can check his facts. Plutarch writes about him with “blasphemy and slander lie beneath his smooth, delicate surface and we must beware of unconsciously accepting his false and absurd ideas about the greats noblest cities and men of Greece.”
He is generally reliable when it comes to the principal events, even though he is prone to exaggerate the size of the Persian armies brought against Greece. He is not, however, as useful when it comes to analysis, particularly his judgements about causes for events or tactics in battles. He openly declares his admiration for Athens and his accounts are largely written from the Athenian point of view. However, it must be remembered that he received his information at a time when Athens and Sparta were hostile to one another, after 464. This could be a contributing factor as to why he writes as if there wasn’t unity between the Greeks.
Herodotus dismisses the idea that the Greeks were ever unified. In his writings he gives endless examples of how the Greeks fought with each other constantly. He describes bribery, treachery and blackmail amongst the Greek camps. One of these descriptions is that of Ephilates who showed the Persians the secret pass to the Spartans in the battle of Thermopylae. He believed that if the Greeks were actually unified, it was accidental and never planned. Some modern historians tend to agree with this opinion.
In the battle of Marathon, a Persian armada of 600 ships embarked on an invasion force of approximately 20, 000 infantry and cavalry on Greek soil just north of Athens. Their mission was to crush the Greek states in retaliation for their support of their Ionian cousins who had revolted against Persian rule. Athens mobilized 10, 000 hoplite warriors to defend their territories. The two armies met on the Plain of Marathon which was ideal for Persian cavalry.
The Athenians asked the Spartans for aid in the battle but according to Herodotus, the Spartans were unable to come straight away as they had their religious festival on at the time; “And the Spartans wished to help the Athenians, but were unable to give them any present succour, as they did not like to break their established law.” They did say that they would come as soon as it was over as quickly as they could which shows the unity at the time between Athens and Sparta, the two main forces at the time. When Athens was in need, Sparta would come to help. Herodotus states “After the full of the moon, two thousand Lacedaemonians came to Athens. So eager had they been to arrive in time that they took but three days to reach Attica from Sparta.”
But it wasn’t unity that helped the Greeks win this battle, they were at a slight advantage as they had knowledge of their land unlike the Persians who had no understanding of the Greek geography as it was very different to their own. The greeks knew the Plain of Marathon well and could use the rugged land and the mountains surrounding the plain to their advantage. The Athenians kept in the high land whereas the Persians stationed themselves on the plain.
Another thing that helped the Greeks win was the absence of the Persian cavalry when the Athenians decided to attack. The cavalry was one of...