Sentence:  The <WSD>Eleutherian</WSD> festival was a long-established panhellenic festival, held every four years. It honoured Zeus Eleutherius, protector of the freedom ("eleutheria") from barbarian dominion which the victory on this spot had secured for the Greeks of former times. 
Meaning of the word marked with <WSD> tags:  Pertaining to Eleutheria, the personification of freedom, or Zeus Eleutheria, the protector of freedom.