The Great Mahabharat War started on Shubhakrit Margashirsha Bright 13/14th Day, Tuesday in Bharani Star, 3137 BC. On the previous day 11/12th Day, when the armies were rehearsing Vyuhas, Arjuna became bewildered, providing the opportunity for Lord Krishna's famous discourse (Bhagavad-Gita) to manifest.
The Glory of the Gita
All the Upanisads are like a cow, and the milker of the cow is Sri Krishna, the son of Maharaj Nanda.
Arjuna is the calf, the sweet nectar of the Gita is the milk, and the fortunate devotees of fine theistic intellect are the drinkers and enjoyers of that milk.