Valmiki Ramayana Ayodhya Kanda Sarga 110 Shloka 6
Original Shlokaविवस्वान्काश्यपात् जज्ञे मनुर्वैवस्वत: स्वयम्। स तु प्रजापतिः पूर्वमिक्ष्वाकुस्तु मनो: सुतः।।2.110.6।।
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काश्यपात् from Kasyapa, विवस्वान् Vivaswat (Sun), जज्ञे was born, मनुः Manu, वैवस्वतः Vivaswat's, सुतः son, स तु as for him, पूर्वम् first, प्रजापतिः Prajapati, इक्ष्वाकुः Ikshvaku, मनोः Manu's, सुतः son.
Kasyapa begot Vivaswat (the Sun) and Vivaswat, Manu. This Manu was the first Prajapati to him whom was born Ikshvaku.