During the persecutions stirred up by the Arian Empress Justina, a.d. 385–6, referred to in his 20th letter, St. Ambrose and the faithful spent the whole night in the basilica, and the holy Bishop employed the people in singing psalms and hymns. A large number of hymns have been attributed to St. Ambrose, the number having by some editors been brought down to twelve, of which, however, only four are certainly his compositions.