Sagara and sixty thousands sons
King Sagara (सगर) was king of Ayodha. He has two wives Keshini (केशिनी) and Sumati (सुमति)
King Sagara doesn’t have any child, so he along with his wives went to a peak named as Bhriguprasravana (भृगुप्रस्रवण) in Himalayas to perform tapasya.
After performing tapasya for 100 years, Rishi Bhrighu (भृगु) Blessed him and said :
एका जनयिता तात पुत्रं वंशकरं तव।
षष्ठिं पुत्रसहस्राणि अपरा जनयिष्यति !! — Ramayana, Balakanda chapter 38, verse 8
“One wife will give birth to a son who will keep your race and the other wife will give birth to sixty thousand sons”
Keshni gave birth to one son named Asamanjasa (असमञ्ज ) and Sumati gave birth to a gourd like foetus and when it burst open, sixty thousand sons emerged. They all were placed in pots filled with clarified butter. They attained adolescence after a long time.
Asamanjasa’s son was Anshuman (अंशुमान्)