Edict that Women should not meet with the Men in the Churches
Accordingly he passed a second law, which enjoined that men should not appear in company with women in the houses of prayer, and forbade women to attend the sacred schools of virtue, or to receive instruction from the bishops, directing the appointment of women to be teachers of their own sex. These regulations being received with general ridicule, he devised other means for effecting the ruin of the churches. He ordered that the usual congregations of the people should be held in the open country outside the gates, alleging that the open air without the city was far more suitable for a multitude than the houses of prayer within the walls.
Source: Life of Constantine (New Advent)