History
For detailed coverage of earlier history of Greece, see Aegean civilizations and ancient Greek civilization.
The geophysical structure of Greece played a significant role in shaping its pre-Classical and Classical history and continued to be influential into the medieval period, for, in spite of the administrative unity and relative effectiveness of the fiscal and military administration of the later Roman and Byzantine states, these still had to function in a geophysical context in which communications were particularly difficult. The southern Balkan Peninsula has no obvious geographic focal point. The main cities in the medieval period were Thessalonica (Modern Greek: Thessaloníki; historically, also called Salonika) and Constantinople, yet these were peripheral to the peninsula and its fragmented landscape. The degree of Byzantine political control during the Middle Ages is clearly reflected in this. In the largely inaccessible Rhodope (Rodópi) Mountains, as well as in the Pindus (Píndos) Mountains, state authority, whether Byzantine or Ottoman, always remained a rather distant factor in the lives of the inhabitants.
The relationship between this landscape of mountains, gulf-indented coasts, and valleys on the one hand and the sea on the other is fundamental to the cultural as well as to the political and the military history of Greece. The sea surrounds Greece except along its northern border; the extended coastline, including such gulfs as those of Corinth (Korinthiakós) and Thessalonica, which penetrate deep into the interior, has served as a means of communication with surrounding areas to the extent that even interior districts of the Balkans often share in the Mediterranean cultural world. The sea was also a source of danger: seaborne access from the west, from the south, or from the northeast via the Black Sea made Greece and the Peloponnese (Pelopónnisos) particularly vulnerable to invasion and dislocation.