The largest socioeconomic, political and cultural centre of the north-western edge of the Black Sea was Olbia Pontica. The name with which it was earlier known (i.e. from the time of its establishment) was Borysthenes. Later, mainly after the third quarter of the 6th cent. BC, the phrase Olbie polis (hence Olbiopolis) was shortened to Olbie, replacing the earlier name Borysthenes; the later name did not disappear altogether though.