Projekat naftovoda zasnovan je na trilateralnom sporazumu koji su u martu 2007. u Atini potpisali Putin, tadašnji grčki premijer Costas Karamanlis i bivši bugarski premijer Sergei Stanishev.
The pipeline's design is based on a trilateral agreement signed in March 2007 in Athens by Putin, then Greek Prime Minister Costas Karamanlis and former Bulgarian Prime Minister Sergei Stanishev.