Shatrughna and Laxman were sons of the second queen Sumitra, wife of Dashratha, the King of Ayodhya. Shatrughna mirrored many aspects of Lakshmana's personality and character.Lakshman followed the footsteps of the paragon of truth, Rama while Shatrughna was equally attached to the unworldly and devoted Bharat, son of Kaikey, and followed him everywhere for he knew that Bharat was a complete devotee of Rama. In Bharat's life, there was no other goal loftier than service to his brother.
During the Sita Swayamvar, when Sita was wedded to Rama, Raja Janak arranged for the wedding of Shatrughna to Shrutkirti, the daughter of his brother Kushadhvaja. Bharat was married to Mandavi and Urmila to Lakshman.
When Bharat placed Rama's charan paduka (sandals), on the throne and went to live in far a away Nandigrama in a straw hut, he lived there for fourteen years, awaiting the arrival of Shri Rama. It was Shatrughna who assumed the mantle of royal duties and the running of the Kingdom.
For fourteen years he ruled, like an alert soldier and administrator. He made sure that the Queen mothers did not feel the absence of their sons. His guru had justly named him for he very ably overpowered all evil forces and enemies of the state and the subjects.
After fourteen years, Rama Lakshman and Sita returned to Ayodhya. Guru Vashistha arranged for the coronation of Rama. In those days, Daityas Madhu's son Lavanasura was creating havoc in Madhuvan (forest called Madhu), making the subjects very unhappy. Shatrughna then requested Rama, the world knows the many ways in which Lakshman has served you. Give me a chance to prove my Kshatriya (warrior caste) value by killing Lavanasura and serving you. Rama gave him the permission. Shatrughna killed Lavanasura and established the kingdom of Madhupur, which later came to be known as Mathura. Raja Rama made Shatrughna the king of Madhupur.
When Rama conducted the Ashwamegh Yagna (horse sacrifice where a horse is let loose and whichever kingdom that horse crosses into has to accept the owner of the horse as their lord or then fight with them), it was Shatrughna who leaded the horse Dig Vijay and made the yagna successful. Shatrughna was also a part incarnation of Vishnu.
By looking after the welfare of the family, the queens, the subjects and the kingdom, Shatrughna gave a stellar proof of his ideal character. He is equal to Bharat and Rama in his goodness and nobility.