The balance of the three eastern powers was upset by the death of Ptolemy Philopator and by the accession of a child to the throne of Egypt. In the winter of 203–202 Philip of Macedon and Antiochus of Syria formed a disgraceful alliance to share between themselves Egypt’s possessions in Europe and Asia, although neither party probably intended to remain loyal to the terms of partition. As the lion’s share was to fall to Antiochus, he was probably the moving spirit.2 In the spring of 202 he invaded southern Syria, while Philip, at first avoiding a direct breach with Egypt, attacked with a newly built fleet some cities along the Bosphorus, some being free and independent while others were allied with or dependent on other communities: Lysimacheia, Chalcedon, and Cius were allies of Aetolia; Perinthus was a dependency of Byzantium; Thasos at this date was a free island. Philip’s capture of Cius with the help of Prusias of Bithynia angered the Aetolians, displeased Antiochus, and led the Rhodians to decide to oppose Philip; their ambassadors had appealed in vain for the town and were forced to see it sacked. Then in 201 Philip annexed the Cyclades and occupied Samos. The precise order of subsequent events is uncertain, but Philip probably first suffered considerable losses in an indecisive naval engagement off Chios, then attacked Pergamum by land and ravaged its territory, next defeated the Rhodian fleet at Lade (near Miletus) and finally operated in South Caria where he was forced to winter.3
Philip’s wanton atrocities against unoffending cities in peacetime had indeed stirred up a hornets’ nest. The violence of his actions, which made war inevitable, may have been due to a desire to settle his accounts while Rome was still engaged with Hannibal. In that case he miscalculated, for Zama was being fought and the Romans would soon be free. But he may have derived some encouragement from the fact that in 202 (autumn) they had coldly rebuffed an Aetolian embassy, which had come to appeal on behalf of their wronged allies; Rome had not forgiven Aetolia for making peace with Philip in 206.4 In the following autumn Attalus and the Rhodians also sent ambassadors to Rome to seek help. Rhodes’ relations with Rome were somewhat strained: while remaining neutral in the First Macedonian War she had denounced Rome’s interference. Attalus, however, was on good terms with Rome, but as he was not technically an ‘ally’ or perhaps even a ‘friend’, there was no legal ground for Rome to intervene. The Senate took no immediate open action but it suddenly reversed its earlier policy towards the eastern situation. One of the consuls elected for 200 was P. Sulpicius Galba, who had campaigned as proconsul in Macedon from 210 to 206; and when the new consuls entered office in March 200 Macedonia was allotted as a consular province to Sulpicius.
Why the Senate wanted war must be considered later, for it is a matter of conjecture rather than of proved fact. How the Senate precipitated war is the present question, for it had apparently to drive two unwilling parties into conflict: the Roman people and Philip. Towards Rome Philip’s conduct had been legally correct and offered no formal ground for reproach; and the Roman people unanimously rejected the consuls’ proposal, made in March 200, that war should be proclaimed.5 It was then decided to present Philip with an ultimatum, so strongly worded that he would be unlikely to accept its terms; these were that he should make reparation to Attalus (as if he, Philip, were the aggressor) and should not make war on any Greek state (as if Rome was allied to any Greeks and could demand their protection). Three ambassadors were sent, probably in the spring of 200, to carry this ultimatum through Greece to Philip who had returned to Macedonia; at the same time they were to stir up pro-Roman feeling in Greece itself, to confer with Attalus and Rhodes, and to visit Syria and Egypt with the object of mediating between the two countries and sounding Antiochus’ real intentions.6
In Greece the ambassadors were received none too cordially until they reached Athens, where events played into their hands. By a selfish neutrality the Athenians had kept out of the national movements of Greece but had recently been forced to face the question of friendship or enmity towards Philip. They had put to death two Acarnanian citizens who had forced their way into the Eleusinian Mysteries (autumn 201), and in the following spring the Acarnanians responded by devastating Attica with help from their ally Philip. Athens did not reply by an immediate declaration of war on Philip, but received help from Rhodes and Attalus when a Macedonian squadron seized four of her warships. Thus when the Roman ambassadors reached the Piraeus they met Attalus who, with the help of Rome’s promise to assist, persuaded Athens to declare war on Philip (about May 200); however much Rome may have contributed to this decision the responsibility must ultimately rest on Athens herself. When Nicanor, a Macedonian commander, attacked the suburbs of Athens, the Romans intervened and gave him Rome’s ultimatum to take to Philip. Then, as their anti-Macedonian appeals found little favour with the Aetolians and Achaeans, the Roman embassy went to Rhodes.
When the Athenians sent a certain Cephisodorus to Egypt, Rhodes, Pergamum, Crete and Aetolia, he obtained little direct help and proceeded to Rome which he reached in July, about the time when the Senate again appealed to the Roman people to declare war on Philip, this time with success.7 Meanwhile Philip sent a general to ravage Attica, and he himself after campaigning in Thrace besieged Abydos. Here he received a formal indictio belli from Aemilius Lepidus, one of the Roman ambassadors from Rhodes. In order to leave Philip no loophole, further demands were added to the previous ultimatum, namely, that he should make reparation to Rhodes as well as Attalus, and should respect all Egyptian dependencies. Philip accepted the challenge, stormed Abydos and returned home where he learnt that Sulpicius had landed near Apollonia with two legions. The Roman ambassadors meanwhile proceeded to Antiochus in the hope of securing his neutrality, and were met with cordiality and evasion. On their way back to Rome they called at Alexandria to report their failure to mediate with Antiochus.