Image source: Michelangelo, Public domain, via Wikimedia Commons
During the 4 years that it took Michelangelo to finish his work on the frescoed ceiling,
he led an incredibly unhealthy life. He spent almost all of his time indoors,
suffered from insomnia, and ate badly and irregularly. In addition, the drinking water
in Rome had a very high calcium concentration. The accumulated effect of all those
factors often causes kidney problems. During that time, Michelangelo began
experiencing the first symptoms of kidney dysfunction which later
developed into renal failure and eventually killed him.
Thanks to his broad anatomical knowledge, developed through illegal dissections,
Michelangelo had an in-depth understanding of the structure and function of
the kidneys. In The Separation of Land and Water, the artist hints
that he had demystified the secrets of the human body,
by inserting key details of the kidney structure into
God's wrinkled royal purple robes.