Tvashtri was a god who was believed by many to have no father or mother. He created a son named Trisiras who had three heads. With one head he observed, with another he ate and with the last he read the Vedas. Trisiras became very powerful very quickly because he had three heads. Another god named Indra was jealous of Trisiras and cut off all three of his heads. Trisiras' father Tvashtri was angry and created Vritra, a large dragon, to harrass Indra.
Prior to the Vedas, the Aryan civilization believed there was harmony in heaven. So this new development in their Vedas introduced the idea of "war in heaven" 250 to a 700 years before "J" began writing the first segments of the Old Testament of the Bible. Many interesting parallel plot lines can be seen such as father gods with no parentage, gods with three heads (trinity-like), evil jealous gods making war with the god's son, dragons, and last but not at all the least war in heaven. It was certainly a idea-rich environment as "J" wrote down the national history of Israel.
This may be the very spot in history where the idea of war in heaven came from.