Council of Chalcedon, Canon XXIII

It has come to the hearing of the holy Synod that certain clergymen and monks, having no authority from their own bishop, and sometimes, indeed, while under sentence of excommunication by him, betake themselves to the imperial Constantinople, and remain there for a long time, raising disturbances and troubling the ecclesiastical state, and turning men’s houses upside down.  Therefore the holy Synod has determined that such persons be first notified by the Advocate of the most holy Church of Constantinople to depart from the imperial city; and if they shall shamelessly continue in the same practices, that they shall be expelled by the same Advocate even against their will, and return to their own places.

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