According to
Vasari's text
The Lives of the Artists, written 140 years after the completion of
St. Mark, the linen workers' guild originally rejected the sculpture because it appeared unnatural when set at street level. This was due to proportion adjustments made for its final resting place in the niche, well above street level. The head and torso were made larger as they would be further away from the viewer. Donatello promised to make adjustments, so he covered the statue with a cloth, set the statue in the niche above the street, and without touching the statue for 15 days, once again revealed it to the guild. With its location above the viewer, the proportions looked perfect and the linen weaver's guild accepted the statue. ==Sources==