From the Bollandist Facebook page (hat tip: William Campbell):

“ML” writes:

21 May: The Ascension of the Lord. One of the oldest depictions of Jesus’ Ascension is an ivory plaque, produced around 400 in Rome or Milan and now kept in the Bayerische Nationalmuseum, Munich. It is contemporary to the establishment of the Feast of the Ascension and as such a unique testimony to how the theological reflection and artistic imagination regarding this mystery of faith developed. The image combines the Ascension with the Resurrection (with Constantine’s Church of the Holy Sepulchre in the background), but more importantly, it shows to what extent Early Christian art was a product of the Late Antique market: Christ does not ascend to heaven, but is literally given a hand by God. The Christian literati rich enough to command such a plaque would have appreciated this depiction, familiar to them from the image of the goddess Athena lifting up the hero Hercules at his apotheosis, or the coins of the consecration of Constantine, which show him ascend his chariot with his arm stretched out towards a hand from heaven. Was this association of Jesus with the demigods of this world merely an artistic devise, or did the heresy of Arianism, still rampant around 400, play a role as well?