One of Gianlorenzo's first commissions in St. Peters, was to design a great canopy in bronze to go over the gravesite of St. Peter.
He received this commission from Urban VIII Barberini, the Pope who made Bernini the chief architect of St. Peters upon his (Urban)
election to the Papacy in 1624.

The design of the Baldechino came from the twisted columns salvaged from the old original Constantinian basilica that had been
demolished in order to construct the new basilica. On the far right of this image, you can barely see in the upper niche
of the great pier, one of these old columns that has been preserved and used in the new constructiion.

The new Baldechino demanded enormous quantities of bronze, and some of this was taken from the underside of the porch
roof of the Pantheon.
At the time, this gave rise to the famous quip that "What wasn't taken by the barbarians, was taken by the Barberini",,,
a reference (in Latin) to the Urban VIII, the Barberini Pope who commissioned the work, which is both architectural and sculptural.

Some seven stories high, the Baldechino is a great Baroque monument to both its creator, Bernini, and to its patron, Urban VIII Barberini,
and arguably the most glorious tomb marker the world has ever seen.