no real ethnic difference between Macedonians and Greeks, only a political distinction contrived after the creation of the League of Corinth in 337 BC (which was led by Macedonia through the league's elected hegemon Philip II, despite him not being a member of the league itself). Hatzopoulos stresses the fact that Macedonians and other peoples such as the Epirotes and Cypriots, despite speaking a Greek dialect, worshiping in Greek cults, engaging in panhellenic games, and upholding traditional Greek institutions, nevertheless occasionally had their territories excluded from contemporary geographic definitions of "Hellas" and were even considered non-Greek barbarians by some. Other academics who concur that the difference between the Macedonians and Greeks was a political rather than a true ethnic discrepancy include Michael B. Sakellariou, Robert Malcolm Errington, and Craige B. Champion. Another perspective interprets the literary evidence and the archaeological-cultural differences between Macedonia and central-southern Greece before the 6th century and beyond as evidence that the Macedonians were originally non-Greek tribes who underwent a process of Hellenization. Accepting that political factors played a part, they highlight the degree of antipathy between Macedonians and Greeks, which was of a different quality to that seen among other Greek stateseven those with a long-term history of mutual animosity (e.g. Sparta and Athens). According to these scholars, the Macedonians came to be regarded as "northern Greeks" only with the ongoing Hellenization of Macedonia and the emergence of Rome as a common enemy in the west. This coincides with the period during which ancient authors such as Polybius and Strabo called the ancient Macedonians "Greeks". By this point, as described by Isocrates, to have been a Greek could have defined a quality of culture and intelligence rather than a racial or ethnic affinity. In the context of ethnic origins of the companions of the Antigonid kings, James L. O'Neil distinguishes Macedonians and Greeks as separate ethnic groups, the latter becoming more prominent in Macedonian affairs and the royal court after Alexander the Great's reign. Others have adopted both views. According to Sansone, "there is no question that, in the fifth and fourth centuries, there were noticeable difference between the Greeks and the Macedonians," yet the issue of Macedonian Hellenicity was ultimately a "political one". Hall adds, "to ask whether the Macedonians 'really were' Greek or not in antiquity is ultimately a redundant question given the shifting semantics of Greekness between the 6th and 4th centuries