Canto 1 - Boyhood
Bāla-kāṇḍa
Chapter 63: Viśvāmitra Falls Prey to Lust
Text 1.63.16

तस्य वर्षसहस्रं तु घोरं तप उपासतः।
उत्तरे पर्वते राम देवतानामभूद्भयम्॥

tasya varṣa-sahasraṁ tu ghoraṁ tapa upāsataḥ
uttare
parvate rāma devatānām abhūd bhayam

tasya = while he; varṣa-sahasram tu = for a thousand years; ghoram tapaḥ = terrible austerities; upāsataḥ = performed; uttare parvate = by the Himālaya in the north; rāma = O Rāma; devatānām abhūt bhayam = the demigods became afraid.

O Rāma, while he performed terrible austerities for a thousand years by the Himālaya in the north, the demigods became afraid.