Albero Della Vita

“We come finally to the most intriguing and original feature of Michelangelo’s design, the central oval with supports Marcus Aurelius at the apex of gentle domical mound. Tolnay has persuasively suggested that the design may be connected with the medieval designation of the Campidoglio as the umbilicus or Caput Mundi…”
The Architecture of Michelangelo
James S. Ackerman