Valmiki Ramayana Bala Kanda Sarga 61 Shloka 5
Original Shlokaएतस्मिन्नेव काले तु अयोध्याधिपतिर्नृप:। अम्बरीष इति ख्यातो यष्टुं समुपचक्रमे।।1.61.5।।
1 source checked for this shloka
एतस्मिन् at that, काले एव time itself, अम्बरीष: इति as Ambarisha, ख्यात: wellknown, अयोध्याधिपति: lord of Ayodhya, नृप: king, यष्टुम् to perform sacrifice, समुपचक्रमे commneced.
At this time Ambarisha, a wellknown king of Ayodhya, launched preparations for a sacrifice.