Valmiki Ramayana Bala Kanda Sarga 5 Shloka 1
Original Shloka. सर्वा पूर्वमियं येषामासीत्कृत्स्ना वसुन्धरा । प्रजापतिमुपादाय नृपाणां जयशालिनाम् ।।1.5.1।।
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सर्वाः all (bounded by all islands), कृत्स्ना entirely, इयं वसुन्धरा this earth, प्रजापतिम् उपादाय commencing from Prajapati (Manu) and his descendents, जयशालिनाम् of victorious, येषां नृपाणाम् relating to those kings, पूर्वम् in the olden periods, आसीत् belonged.
Formerly, this entire earth belonged to those victorious kings starting from Prajapati (Manu). Dasaratha's kingdom and greatness of Ayodhya