Addressed to the Emperor Theodosius after the massacre at Thessalonica. The mob at Thessalonica had barbarously murdered a number of the officers of the garrison of that city. The Emperor, being exceedingly angry, sent orders in obedience to which over seven thousand of the inhabitants were cruelly put to death. This act of vengeance shocked the public conscience, and St. Ambrose felt it his duty to speak out in the name of the Church. St. Ambrose begins by stating his reasons for not having met the Emperor on his return to Milan. He then mentions the sentiments of the bishops with regard to the slaughter at Thessalonica, and points out that repentance for that deed is necessary to obtain forgiveness and a victory over the devil, the instigator to that crime. St. Ambrose could not offer the sacrifice in the Emperor’s presence, and, as truly loving the Emperor, grieves and yet hopes.