Vishvamitra is a king who visits the brahmin Vasishtha's woodland ashram with a contingent of retainers.
When Vishvamitra asks for food, he is astounded by Vasishtha's cow, the Kamadhenu's capacity to feed everyone.
Vishvamitra attempts to purchase the Kamadhenu first, then
tries to seize it by force, but his henchmen are thwarted by Vasishtha's tapas'
magical abilities (ascetic practices).
Vishvamitra ultimately accepts defeat and undertakes ascetic
practices in order to generate his own strength.
Two of their most famous battles are over King Trishanku and
his son, Harishchandra; in each instance, the actual problem is the sages'
mutual hatred.