Demosthenes grew interested in politics during the time he wrote speeches for others. In 354 BC he gave his first public political speeches. He went on to devote his most productive years to opposing Macedon's expansion. He idealized his city and tried throughout his life to restore Athens' supremacy and motivate the rest of the Athenians against Philip II of Macedon. He sought to preserve his city's freedom and to establish an alliance against Macedon, in an unsuccessful attempt to impede Philip's plans to expand his influence southwards by conquering all the Greek states. After Philip's death, Demosthenes played a leading part in his city's uprising against the new King of Macedon, Alexander the Great. However, his efforts failed and the revolt was met with a harsh Macedonian reaction. To prevent a similar revolt against his own rule, Alexander's successor, Antipater, sent his men to track Demosthenes down. Demosthenes took his own life, in order to avoid being arrested by Archias, Antipater's confidant.