 Complete the following phrase:  Antiochus III launched a massive campaign to retake Parthia and Bactria in 210 or 209 BC. Despite some victories he was unsuccessful, but did negotiate a peace settlement with Arsaces II. The latter was granted the title of king Greek: basileus in return for his submission to Antiochus III as his superior. The Seleucids were unable to further intervene in Parthian affairs following increasing encroachment by the Roman Republic and the Seleucid 