He first probably finished the siege of Pagasae, to deny the Athenians a landing place in Thessaly. Pagasae was not part of the Thessalian Confederation, and Philip therefore took it as his own, and garrisoned it. The fall of Pagasae now left Pherae totally isolated.
Philip probably ended the siege on Pagasae to prevent Athenians from landing in Thessaly. Since Pagasae was not part of the Thessalian Confederation, Philip took it for himself and garrisoned it. With Pagasae lost, Pherae became completely isolated.