A Byzantine Diagram of the Cosmos

A 16th-century copy of a Byzantine diagram of the geocentric cosmos from Royal MS 16 C XII, fol. 45r.
A 16th-century copy of a Byzantine diagram of the geocentric cosmos from Royal MS 16 C XII, fol. 45r.

This diagram represents the geocentric cosmos, with the earth (γῆ) at the center, surrounded by spheres of the Moon (σελήν), Mercury (ἐρμῆς), Venus (ἀφροδίτη), the sun, Mars (ἄρης), Jupiter (ζεύς), and Saturn (κρόνος).[1] An incomplete ring for the signs of the zodiac encircles the planetary spheres—only the symbol for Aries was added. Finally, the names of the zodiac were labeled in red on the outside, starting at 3 o’clock and proceeding counter clockwise:

  • Aries (κριός)
  • Taurus (ταῦρος)
  • Gemini (δίδυμι)
  • Cancer (καρκίνος)
  • Leo (λέων)
  • Virgo (παρθένος)
  • Libra (ζυγός)
  • Scoprio (σκορπιός)
  • Sagittarius (τοξότης)
  • Capricorn (αἰγώκερως (should be αἰγόκερως))
  • Aquarius (ὕδροχόος)
  • Pisces (ἰχθύες)

This diagram is part of a collection of astronomical diagrams in Royal MS 16 C XII, a latter 16th-century manuscript first owned by the brilliant classical scholar and historian Isaac Casaubon. Other texts in the in the codex all concern the construction and use of the astrolabe (the first text is a printed edition from 1544, the rest are manuscripts).


  1. The ordering of the planets in this diagram poses a bit of a puzzle. As labeled, it suggests that the planetary order was: Moon, Mercury, Venus, Mars, [sun], Jupiter, Saturn. I’ve never come across that order before, i.e., Mars below the sun. What makes more sense is that the sun’s sphere, the fourth from the center, is instead labeled “ἄρης” because Mars’s sphere had been colored black (possibly before labeling any of them). Then, since writing wouldn’t show up on the black sphere, the person labeled Mars on the sphere below it, the sun’s.  ↩