Canto 1 - Boyhood
Bāla-kāṇḍa
Chapter 21: The Anger and Appeasal of Viśvāmitra
Text 1.21.16
पञ्चाशतं सुतान्ल्लेभे जया नाम परान्पुरा।
वधायासुरसैन्यानाममेयान्कामरूपिणः॥
pañcāśataṁ sutānl lebhe jayā nāma parān purā
vadhāyāsura-sainyānām ameyān kāma-rūpiṇaḥ
pañcāśatam = fifty; sutān = sons; lebhe = had given birth to; jayā = Jayā; nāma = [the daughter] named; parān = great; purā = in the past; vadhāya = for the destruction; asura-sainyānām = of the armies of the asuras; ameyān = with indefatigable power; kāma-rūpiṇaḥ = and the ability to change forms
In the past, [the daughter] named Jayā had given birth to fifty great sons with indefatiguable power and the ability to change forms for the destruction of the armies of the asuras.
Who gave birth to how many? That is answered here and in the next verse.