The word "Galungan" comes from the Old Javanese language, which means win or fight. Galungan also synonymous with Dungulan, which also means victory. Because it is in Java, the eleventh wuku called Wuku Galungan, while at the eleventh Wuku Bali called Wuku Dungulan. Name is different, but means the same thing. As in Java in the details there as Legi pancawara while in Bali called Umanis, which means the same: sweet.
Somewhat difficult to ascertain how the origin of this Galungan. When actually celebrated Galungan first in Indonesia, especially in Java and in other areas, especially in Bali. Drs. I Gusti Agung Gede Putra (former Director General of the Hindu and Buddhist Guidance Department of Religious Affairs) estimates, Galungan Hindus have long celebrated in Indonesia before the feast was celebrated in the popular island of Bali. This allegation is based on the Old Javanese language papyrus was named Song of Flag Amalat Rasmi. However, exactly when it celebrated Galungan in from outside, and whether the same name Galungan, still unanswered, for sure.
But in Bali, there are sources that provide a bright spot. According to the Purana Lontar Bali Dwipa, Galungan first celebrated on Purnama Kapat, Budha Keliwon Dungulan (Balinese calendar), or the year 804 Saka year 882 AD.
Galungan core is to unite the spiritual strength to get the mind and the establishment of the light. Spiritual union and the bright minds here in the form of dharma. While all the chaos that thought is a form of adharma.