The Great Year and the Solar Year

A celestial year (the 'Great Year', or year of the ages) consists of app. 24,000 earth years, and begins at the Spring Equinox in Aries. A solar year (365.25 days), begins when the sun 'resurrects' at the winter solstice in the Tropic of Capricorn. 

A solar year follows the sun through the zodiac houses clockwise, whereas a Great Year transits through the houses of the zodiac counter-clockwise.