Attempts to translate astrological symbolism into forms acceptable to Christians began in the early centuries of the Christian era. Leonardo Da Vinci painted his work “The Last Supper” in a time when correspondences between apostles and zodiac signs had been in circulation for well over a thousand years.  (See Walter C. Cambra’s article “The Zodiacal Template” showing Dante’s subtle yet methodical incorporation of the zodiacal wheel into his work The Divine Comedy)
A careful viewing of “The Last Supper” shows six apostles flanking each of Jesus’ right and left sides. These twelve apostles are distinctly presented in groups of three. The four groups of three represent not only the four quadrants of the zodiacal wheel, but also each quadrant’s three signs.