After staying four months in Athens, Alcibiades set sail with a fleet for the Aegean. He attacked the island of Andros, which had recently rebelled against Athens, winning a battle and beginning siege operations against the town. He then sailed on to the main Athenian base in Samos.
The Spartans sent out Lysander as the admiral of their fleet, which he led to Ephesus on the Asian mainland opposite the island of Samos. He set his fleet in order and waited for the arrival in Sardis of a new Persian commander. The Persians had sent out a new leader with extraordinary powers, Prince Cyrus, son of the Great King Darius. He came with the title of Karanos or Viceroy of the maritime provinces of Asia Minor, Lydia, Greater Phrygia, and Cappodocia.