Translation - Engleski-Grcki - Free Spirit, Know thyself.

It´s the inscription in the Delphos Oracle, from the greek mythology. It´s seem in the Matrix trilogy too.

Thyself is an old and more nobre form of "yourself"

I chose ancient (Attic) Greek, since it refers to the oracle from Delphi. (Έλευτερη for Ionic Greek)