Henry Morgenthau, Sr. quote: “When the Turks and the Bulgarians left, Macedonia remained a purely Greek region.”

“Macedonia as a whole tended to remain in isolation from the rest of Greece…”

Peter Green (1924) British historian

Alexander the Great, page 20.

“Thessalonica remained Greek and the capital of the country”

Theodor Mommsen (1817–1903) German classical scholar, historian, jurist, journalist, politician, archaeologist and writer

The Provinces of the Roman Empire, vol.1, translated by W.P.Dickson, from the 1909 edition (Chicago, Ares Publishers, 1974), pp. 299–301.
The Provinces of the Roman Empire, From Caesar to Diocletian 1854-6
Context: While the Macedonians proper on the lower course of the Haliacmon (Vistritza) and the Axius (Vardar), as far as the Strymon, were an originally Greek stock, whose diversity from the more southern Hellenes had no further significance for the present epoch, and while the Hellenic colonization embraced within its sphere both coasts -on the west with Apollonia and Dyrrachium, on the east in particular with the townships of the Chalcidian peninsula - the interior of the province, on the other hand, was filled with a confused mass of non-Greek peoples, [... ] The Greek cities, which the Romans found existing, retained their organisation and their rights; Thessalonica, the most considerable of them, also freedom and autonomy. There existed a League and a Diet ('koinon') of the Macedonian towns, similar to those in Achaia and Thessaly. It deserves mention, as an evidence of the continued working of the memories of the old and great times, that still in the middle of the third century after Christ the diet of Macedonia and individual Macedonian towns issued coins on which, in place of the head and name of the reigning emperor, came those of Alexander the Great. The pretty numerous colonies of Roman burgesses which Augustus established in Macedonia, Byllis not far from Apollonia, Dyrrachium on the Adriatic, on the other coast Dium, Pella, Cassandreia, in the region of Thrace proper Philippi, were all of them older Greek towns, which obtained merely a number of new burgesses and a different legal position, and were called into life primarily by the need of providing quarters in a civilised and not greatly populous province for Italian soldiers who had served their time, and for whom there was no longer room in Italy itself. The granting of Italian rights certainly took place only to gild for the veterans their settlement abroad. That it was never intended to draw Macedonia into a development of Italian culture is evinced, apart from all else, by the fact that Thessalonica remained Greek and the capital of the country.

“All in all, the language of the Macedones was a distinct and particular form of Greek, resistant to outside influnces and conservative in pronunciation. It remained so until the fourth century when it was almost totally submerged by the flood tide of standardized Greek.”

N. G. L. Hammond (1907–2001) British classical scholar

"A History of Macedonia" Vol ii, 550-336 BC

“Against this view, it is still possible to identify some cultural continuities. Kitromilides himself alludes to some of them, when he mentions “inherited forms of cultural expression, such as those associated with the Orthodox liturgical cycle and the images of emperors, the commemoration of Christian kings, the evocation of the Orthodox kingdom and its earthly seat, Constantinople, which is so powerfully communicated in texts such as the Akathist Hymn, sung every year during Lent and forming such an intimate component of Orthodox worship...“ (Kitromilides 1998, 31). There are other lines of Greek continuity. Despite the adoption of a new religion, Christianity, certain traditions, such as a dedication to competitive values, have remained fairly constant, as have the basic forms of the Greek language and the contours of the Greek homeland (though its centre of gravity was subject to change). And John Armstrong has pointed to the “precocious nationalism” that took hold of the Greek population of the Byzantine Empire under the last Palaeologan emperors and that was directed as much against the Catholic Latins as against the Muslim Turks—an expression of medieval Greek national sentiment as well as a harbinger of later Greek nationalism. But again, we may ask: was this Byzantine sentiment a case of purely confessional loyalty or of ethnoreligious nationalism?”

Anthony D. Smith (1939–2016) British academic

See Armstrong 1982, I74—8I cf. Baynes and Moss 1969, 119—27, and Carras 1983.
Source: The Nation in History (2000), p. 42-43.

“The pure religious consciousness lies in a region which is forever beyond all proof or disproof.”

Walter Terence Stace (1886–1967) British civil servant, educator and philosopher.

p. 136

“Modern Slavs, both Bulgarians and Macedonians, cannot establish a link with antiquity, as the Slavs entered the Balkans centuries after the demise of the ancient Macedonian kingdom. Only the most radical Slavic factions—mostly émigrés in the United States, Canada, and Australia—even attempt to establish a connection to antiquity […] The twentieth-century development of a Macedonian ethnicity, and its recent evolution into independent statehood following the collapse of the Yugoslav state in 1991, has followed a rocky road. In order to survive the vicissitudes of Balkan history and politics, the Macedonians, who have had no history, need one. They reside in a territory once part of a famous ancient kingdom, which has borne the Macedonian name as a region ever since and was called ”Macedonia” for nearly half a century as part of Yugoslavia. And they speak a language now recognized by most linguists outside Bulgaria, Serbia, and Greece as a south Slavic language separate from Slovenian, Serbo-Croatian, and Bulgarian. Their own so-called Macedonian ethnicity had evolved for more than a century, and thus it seemed natural and appropriate for them to call the new nation “Macedonia” and to attempt to provide some cultural references to bolster ethnic survival..”

Eugene N. Borza (1935) American historian

"Macedonia Redux", in "The Eye Expanded: life and the arts in Greco-Roman Antiquity", ed. Frances B Tichener & Richard F. Moorton, University of California Press, 1999