The region which constitutes nowadays the Prefecture of Phocis was covered in antiquity by the territory of several ethnicities, such as the West Locrians, the Dorians, the Oeteans, the Aetolians and the Phocians. In the region of the latter is located the sanctuary of Delphi. Phocis was one of the relatively small regions of ancient Greece, with a total surface of 1,800 klms; in antiquity it bordered with the land of the Opuntian Locrians, with Boeotia, with the land of the Ozolian Locrians as well as with Doris. Although it was a mountainous region, its geographical location, which controlled the communication between Eastern and Western Mainland Greece, as well as between Northern and Southern Greece, made its inhabitants in several cases regulators of important political and military events. 

Archaic and Classical Periods: The Phocian League
In the Iliad are mentioned nine Phocian cities which sent ships to Troy under the joint leadership of Epistrophos and Schedios (2. 517-520). 
The Phocians would probably not have formed an autonomous political entity, had they not faced the political pressure of the Thessalians, who managed to conquer Phocis in 595 B.C., during the First Sacred War. The reason was the fame and power that the sanctuary of Delphi (controlled, so far by the inhabitants of Krissa) had acquired meanwhile.  The control of the sanctuary would influence the political and military decisions which affected not only Greece but also all the Greek communities all over the then known world.  Under Thessalian tutelage, the Phocians united and finally created a federal state, the Phocian League, with a common bouleuterion (Phokikon)  and common coinage. All the cities participated equally in the confederation. 
Elateia was the capital of the Phocian League. Coins were initially minted in Elateia, Lilaea, Antikyra and Ledon. Some of the aforementioned cities nowadays belong to Boeotia and some in Phocis, whereas Elateia, capital of the League, and Amphikleia, are situated in Phthiotis. 

Delphi and the Phocian League
By looking at the catalogue of the cities which constituted the Phocian League, one is stricken by the absence of Delphi. The fact is that the Phocians coveted the sanctuary and its incomes and they  thought that they should control it politically. Delphi, however, as see of the Amphictyony, wanted to be autonomous. Several times, particularly within the 5th century B.C., the Phocians managed to gain control of the sanctuary, particularly due to their alliances. The Phocians continued to attempt to put under their control the sanctuary of Delphi throughout the 5th and in the largest part of the 4th century B.C., which led to three more sacred wars, namely the Second, the Third and the Fourth.
After Philip II finally established his supremacy in Greece, Phocis followed the fate of the rest of Greece (see "History of Delphi in the Hellenistic period" and "History of Delphi in the Roman period").