The Coronation of the Virgin

Tympanum of the west portal, Senlis Cathedral

This is said to be the oldest sculptural representation of this subject. Mary and the Son wear crowns and sit on matching thrones, flanked by angels.

The lower register is divided vertically into a Dormition and an Assumption. Unlike later Assumptions, the Senlis sculpture has Mary lifted up by angels rather than by Christ himself.

Also see: The upper register, the Assumption scene, the context
Chartres has a tympanum nearly identical in composition but more finely executed.
More of Coronation of the Virgin

Source: Wikimedia Commons