The Warriors is based explicitly on Anabasis ('Uphill') by the soldier/writer Xenophon:
Stranded deep in enemy territory, the ... Greek senior officers killed ... Xenophon, one of three remaining leaders elected by the soldiers, played an instrumental role in encouraging the Greek army of 10,000 to march north across foodless deserts and snow-filled mountain passes towards the Black Sea and the comparative security of its Greek shoreline cities. Abandoned in northern Mesopotamia, without supplies other than what they could obtain by force or diplomacy, the 10,000 had to fight their way northwards through Corduene and Armenia, making ad hoc decisions about their leadership, tactics, provender and destiny, while the King's army and hostile natives constantly barred their way and attacked their flanks. Ultimately this "marching republic" managed to reach the shores of the Black Sea at Trebizond, a destination they greeted with their famous cry of joyous exultation on the mountain of Madur in Surmene : "thalatta, thalatta", "the sea, the sea!".
The Warriors depicts a mixed-race street gang fighting their way out of New York. The film is much less subtle in its exploration of the theme than Southern Comfort or Aliens, for example using the names of characters from the Anabasis, and with explicit discussion about 'who should be the war leader?' It is very interesting to me as a missing link joining up the chain of development, but I prefer the two subsequent films which revisit the theme in a more complex way, and they are both very subtexual.
Incidentally I think Star Trek Voyager could have been a much better show if it had followed this template more closely. In fact it ended up being rubbish.
(ETA - for my classicist friends, why I have used 'thalatta' not 'thalassa': that indented text is from from wikpedia which has the note "θαλασσα... Thalatta was the Attic pronunciation")