The Ascension of Christ

Jesus is "taken up into heaven" in the Ascension narratives in Mark 16:19-20, Luke 24:50-53, and Acts 1:6-12.

The Syriac illumination at left is an early example of what became in the west the most common way of representing this event. Christ is in a mandorla on a chariot, attended by angels, facing the viewer. Below, the Virgin Mary stands in the canter with hands raised in an orant position of prayer flanked by two angels, who apparently are addressing to the apostles the words in Acts 1:11, "Ye men of Galilee, why stand you looking up to heaven?"

It is suggested that the chariot refers to a reading for Ascension Day in the Syriac liturgy from Ezekiel 1. A Syrian ampulla of the same century, however, has all the elements seen at left except the chariot. There is also a quite similar 6th-century Palestinian icon with all but the chariot. Perhaps the mandorla functions visually as a signifier of the chariot.
See: What is Ezekiel's Merkabah?

In any case, a great many western Ascension images adapt the pattern seen in the Syrian image, dispensing with the chariot and sometimes with one or two other details. Thus, Perugino's Ascension omits the two angels on the ground but adds St. Paul. A Florentine illumination from the 14th century has St. Paul but no angels at all. In Renaissance and Baroque images Christ ascends through clouds under his own power rather than borne by angels (example). This seems to reflect the mood of the times, as well as the Golden Legend's firm insistence on self-portation:

And also St. John [3:13] saith: "No man ascendeth into heaven by his own puissance and might, but the Son of Man that is in heaven." And how be it that he ascended in a cloud, he had none need, but because that he would show that every creature is ready to serve his creator, he ascended in his proper virtue.

(Source-The Ascension of Christ)

Also See:
Ascension, Testaments, of Prophets, Apocalyptic Instructions, and Prophetic Warnings
Golden Legend #72
Ascent to Heaven in Antiquity