Cersebleptes continued his attempts to unite the Odrysian kingdoms: in 353/4 he and Philip discussed the invasion of the kingdom of Amadocus II and the Athenian domains in Thrace, while around a year later he marched against the kingdom of Cetriporis. Meanwhile, Athens feared a possiblle alliance between Philip and Cersebleptes and decided to make an example by conquering the town of Sestos and eradicating its population. Intimidated, Cersebleptes renounced his claims on much of the Chersonese and allied with Athens. This was unacceptable for Philip, who allied with Amadocus II and marched against Cersebleptes. After besieging him in his residence in Heraion Teichos in 351, he forced the Thracian king to surrender and took his son as a hostage. Around this time, Philip also abolished Cetriporis' kingdom and deposed Amadocus II in favour of Teres II.