The Kronia (or Cronia) was a very ancient greek festival in honor of Kronos (Cronus) and Rhea, adopted by the Romans in the 5th century BCE as Saturnalia (Saturn = Kronos) and much later by the Christians as Christmas. (Early Christians established holidays for each 'pagan' feast - exactly as christian missionaries and conquistadores did much later in Latin America). The Kronia survived until the 12th century in some parts of Greece including the mountainous south of the Peloponese . Kronos and Rhea were the parents of Dias (Zeus - cf. "dio"). During Kronia (and Saturnalia) masters and slaves would exchange roles so this 'revolutionary' character was what probably attracted early Christians to set Saturnalia as their main festivity. Later, in the 4th c. CE the Byzantine/Roman Emperor Theodosius banned any festivity that had not yet been converted to a Christian one, including the Olympics, while the christian mobs destroyed or "recycled" old religion temples including the Artemis temple in Ephesus one of the 7 wonders. To put Taliban barbarism into perspective.

Related sources: http://ancienthistory.about.com/od/winterh...ys/g/Cronia.htm
(in Greek) http://www.myriobiblos.gr/texts/greek/cons...tiries_ch3.html