Athens was at that time embroiled in a conflict with the neighbouring island of Aegina, which possessed a formidable navy. In order to counter this, and possibly with an eye already at the mounting Persian preparations, in 483/2 BC the Athenian statesman Themistocles used his political skills and influence to persuade the Athenian assembly to start the construction of 200 triremes, using the income of the newly discovered silver mines at Laurion. The first clash with the Persian navy was at the Battle of Artemisium, where both sides suffered great casualties. However, the decisive naval clash occurred at Salamis, where Xerxes’ invasion fleet was decisively defeated.
After Salamis and another Greek victory over the Persian fleet at Mycale, the Ionian cities were freed, and the Delian League was formed under the aegis of Athens. Gradually, the predominance of Athens turned the League effectively into an Athenian Empire. The source and foundation of Athens’ power was her strong fleet, composed of over 200 triremes. It not only secured control of the Aegean Sea and the loyalty of her allies, but also safeguarded the trade routes and the grain shipments from the Black Sea, which fed the city’s burgeoning population. In addition, as it provided permanent employment for the city’s poorer citizens, the fleet played an important role in maintaining and promoting the radical Athenian form of democracy. Athenian maritime power is the first example of thalassocracy in world history. Aside from Athens, other major naval powers of the era included Syracuse, Corfu and Corinth.
In the subsequent Peloponnesian War, naval battles fought by triremes were crucial in the power balance between Athens and Sparta. Despite numerous land engagements, Athens was finally defeated through the destruction of her fleet during the Sicilian Expedition, and finally, at the Battle of Aegospotami, at the hands of Sparta and her allies.