After the fall of Carthage ( 19 October 439), the Vandals severely threatened the whole Mediterranean area, particularly Italy and Rome. They reached Sicily but did not enter Italy. In 442 Valentinian III was obliged to accept the treaty offered by Gaiseric, the Vandal leader.
Alaric had sacked Rome on 28 August 410, and a commemoration of gratitude for Rome's deliverance had been held annually ever since. During the years immediately preceding the treaty with Gaiseric ( 441-442), the first years of Leo's pontificate, people attended the anniversary celebration in great numbers as the Vandals were threatening. After the treaty had been concluded, however, their relief led to anniversary celebrations that were--on this particular occasion at least--very sparsely attended.
"More effort is spent on demons than on the apostles, and the wild entertainments draw greater crowds than the shrines of martyrs. Who restored this city to safety? Who snatched it from captivity? Who protected it from slaughter? Was it the games of the circus, or the watchful care of saints?" ( Serm. 84.1) "Let us attribute our deliverance not, as the pagans think, to the effects of stars, but to the inexpressible mercy of almighty God, who willed to soften the hearts of raging barbarians" ( Serm. 84.2).
30 August or 6 September 442
THAT RELIGIOUS DEVOTION, dearly beloved, with which the whole body of the faithful used to come together to give thanks to God for the day of our chastisement and of our liberation, has recently been neglected by almost everyone, as the very scarcity of the few who were present has shown. It brings much sadness to my heart and produces very great anxiety. There is serious danger in being ungrateful to God and, through forgetfulness of his benefits, feeling neither remorse after his correction nor joy in his pardon.
I fear then, dearly beloved, that the voice of the prophet