Giotto, The Ascension of Christ
Scrovegni Chapel, Padua, Italy
As he did in the Assisi Ascension image, Giotto shows Christ in profile, reaching up toward Heaven, his hands piercing through the frame of the image. This is a vestige of the old iconography that had him striding upward as if climbing a mountain.
Giotto also adapts the mandorla from another iconographic tradition, but not the motif of angels surrounding or helping to lift it. Instead, the angels acclaim him from a bit of a distance.
Below, the Apostles kneel with the Virgin Mary as the two angels of Acts 1 ask them, "why stand you looking up to Heaven?" There are eleven Apostles, because it is not until later in Acts 1 that they choose a twelfth to fill the place left by Judas.
Read more about the Ascension.
Source: Wikimedia Commons