Ramayana
ततः समभवद्युद्धं तुमुलं रोमहर्षणम् । सप्तरात्रं महाभीमं न चान्यतरयोर्जयः ॥ 7-101-5 ॥
Then there arose a tumultuous, hair-raising battle, exceedingly terrible, that lasted seven nights, and the victory belonged to neither of the two sides.
english translation