Council of Chalcedon, Canon XVII

Outlying or rural parishes shall in every province remain subject to the bishops who now have jurisdiction over them, particularly if the bishops have peaceably and continuously governed them for the space of thirty years.  But if within thirty years there has been, or is, any dispute concerning them, it is lawful for those who hold themselves aggrieved to bring their cause before the synod of the province.  And if any one be wronged by his metropolitan, let the matter be decided by the exarch of the diocese or by the throne of Constantinople, as aforesaid.  And if any city has been, or shall hereafter be newly erected by imperial authority, let the order of the ecclesiastical parishes follow the political and municipal example.

Translation: Henry R. Percival, The Seven Ecumenical Councils, NPNF II.14 (1900), via CCEL.