He then set off on a series of campaigns throughout the Aegean. He seized several Athenian-held cities, and attacked numerous islands. He was unable to move north to the Hellespont, however, because of the threat from the Athenian fleet at Samos. To divert the Athenians, Lysander struck westward. Approaching quite near to Athens itself, he attacked Aegina and Salamis, and even landed in Attica. The Athenian fleet set out in pursuit, but Lysander sailed around them, reached the Hellespont, and established a base at Abydos. From there, he seized the strategically important town of Lampsacus. From here, the way was open to enter the Bosporus and close down the trade routes from which Athens received the majority of her grain. If the Athenians were to avoid starvation, Lysander had to be contained immediately.