Valmiki Ramayana Bala Kanda Sarga 55 Shloka 11
Original Shlokaस पुत्रमेकं राज्याय पालयेति नियुज्य च। पृथिवीं क्षत्रधर्मेण वनमेवान्वपद्यत।।1.55.11।।
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स: he, पृथिवीम् the earth, क्षत्रधर्मेण in accordance with the tradition of Kshatriya, पालय rule, इति thus, एकम् one, पुत्रम् son, राज्याय for the kingdom, नियुज्य having appointed, वनमेव forest, अन्वपद्यत reached.
Viswamitra, having entrusted one of his remaining sons to rule the kingdom in accordance with the kshatriya tradition reached the forest.