Council of Ephesus
Council of Ephesus, Canon VI
Selected letters, decrees and canons, including Cyril’s anathemas with reception notes; not the full proceedings
Canon VI
Likewise, if any should in any way attempt to set aside the orders in each case made by the holy Synod at Ephesus, the holy Synod decrees that, if they be bishops or clergymen, they shall absolutely forfeit their office; and, if laymen, that they shall be excommunicated.
Translation: Henry R. Percival, The Seven Ecumenical Councils, NPNF II.14 (1900), via CCEL.
Source: Council of Ephesus (CCEL)