Artaxerxes became involved in a war with Persia's erstwhile allies, the Spartans, during the Corinthian War (395-387 BC).
The Spartans under their king Agesilaus II had started by invading Asia Minor in 396-395 BC.
To redirect the Spartans' attention to Greek affairs, Artaxerxes subsidized their enemies through his envoy Timocrates of Rhodes; in particular, the Athenians, Thebans, and Corinthians received massives subsidies.
Tens of thousands of darics, the main currency in Achaemenid coinage, were used to bribe the Greek states to start a war against Sparta.
These subsidies helped to engage the Spartans in what would become known as the Corinthian War.
According to Plutarch, Agesilaus said upon leaving Asia Minor, "I have been driven out by 10,000 Persian archers", a reference to "Archers" (Toxotai) the Greek nickname for the darics from their obverse design, because that much money had been paid to politicians in Athens and Thebes  to start a war against Sparta.

The Achaemenids, allied with Athens, managed to utterly destroy the Spartan fleet at the Battle of Cnidus (394 BC).
After that, the Achaemenid satrap of Hellespontine Phrygia, Pharnabazus II, together with former Athenian admiral Conon, raided the coasts of Peloponnesia, putting increased pressure on the Spartans.
This encouraged the resurgence of Athens, which started to bring back under her control the Greek cities of Asia Minor, thus worrying Artaxerxes II that his Athenian allies were becoming too powerful.
Artaxerxes became involved in a war with Persia's erstwhile allies, the Spartans, during the Corinthian War (395-387 BC). The Spartans under their king Agesilaus II had started by invading Asia Minor in 396-395 BC. To redirect the Spartans' attention to Greek affairs, Artaxerxes subsidized their enemies through his envoy Timocrates of Rhodes; in particular, the Athenians, Thebans, and Corinthians received massives subsidies. Tens of thousands of darics, the main currency in Achaemenid coinage, were used to bribe the Greek states to start a war against Sparta. These subsidies helped to engage the Spartans in what would become known as the Corinthian War. According to Plutarch, Agesilaus said upon leaving Asia Minor, "I have been driven out by 10,000 Persian archers", a reference to "Archers" (Toxotai) the Greek nickname for the darics from their obverse design, because that much money had been paid to politicians in Athens and Thebes  to start a war against Sparta.
The Achaemenids, allied with Athens, managed to utterly destroy the Spartan fleet at the Battle of Cnidus (394 BC). After that, the Achaemenid satrap of Hellespontine Phrygia, Pharnabazus II, together with former Athenian admiral Conon, raided the coasts of Peloponnesia, putting increased pressure on the Spartans. This encouraged the resurgence of Athens, which started to bring back under her control the Greek cities of Asia Minor, thus worrying Artaxerxes II that his Athenian allies were becoming too powerful.
Artaxerxes II of Persia