who did the spartans ask for help during the second war
Peloponnesian War Following the destruction of the Sicilian Expedition, Lacedaemon encouraged the revolt of Athens's tributary allies, and indeed, much of Ionia rose in revolt against Athens. The Syracusans sent their fleet to the Peloponnesians, and the Persians decided to support the Spartans with money and ships. Revolt and faction threatened in Athens itself.
Battle of Marathon At the time of the battle, Sparta and Athens were the two largest city-states in Greece. Once the Ionian revolt was finally crushed by the Persian victory at the Battle of Lade in 494 BC, Darius began plans to subjugate Greece. In 490 BC, he sent a naval task force under Datis and Artaphernes across the Aegean, to subjugate the Cyclades, and then to make punitive attacks on Athens and Eretria. Reaching Euboea in mid-summer after a successful campaign in the Aegean, the Persians proceeded to besiege and capture Eretria. The Persian force then sailed for Attica, landing in the bay near the town of Marathon. The Athenians, joined by a small force from Plataea, marched to Marathon, and succeeded in blocking the two exits from the plain of Marathon. The Athenians also sent a message asking for support to the Spartans. When the messenger arrived in Sparta, the Spartans were involved in a religious festival and gave this as a reason for not coming to aid of the Athenians.