Something you don't know in Ramayan

Something you don't know in Ramayan
In many scripts and literature, it is written that King Dashrath did not had any sons. This literature is true.  A long time before he gave birth to four sons, who were known as prince of Ayodhya .He had a daughter named Shanta. She was adopted by the King of Ang Desh. She was married off to Rishi Shring. Rishi Shring  did a ritual(Yagya-Ritual is a hindu ceremonial act of sacrificing to their deities in a havan samagri) (of offering to their deities) for King Dashrath to help him achieve his wish to get a son. After the ritual completion, King Dashrath had four sons-Ram, Lakshman, Shtrughan and Bharat.