It Is Necessary To Keep Ones

Giorgio Vasari records this remark in Lives of the Artists (1550, revised 1568) as a statement Michelangelo made about the art of architecture and sculpture. The "compass in the eye" was a Renaissance term for the trained faculty of visual judgment — the ability to assess proportion and correctness by sight rather than relying mechanically on measuring instruments. Michelangelo applied this principle most radically in his work on St. Peter's Basilica in Rome, where he served as chief architect from 1546 until his death, often making adjustments to the structure that had no basis in geometric calculation but depended entirely on his visual intuition.