Srimad-Bhagavatam: Canto 9 - Chapter 1 - Verse 13-14
Sanskrit:
सुबाहु: श्रुतसेनश्च शत्रुघ्नस्य बभूवतु: ।गन्धर्वान् कोटिशो जघ्ने भरतो विजये दिशाम् ॥ १३ ॥तदीयं धनमानीय सर्वं राज्ञे न्यवेदयत् ।शत्रुघ्नश्च मधो: पुत्रं लवणं नाम राक्षसम् ।हत्वा मधुवने चक्रे मथुरां नाम वै पुरीम् ॥ १४ ॥
ITRANS:
subāhuḥ śrutasenaś caśatrughnasya babhūvatuḥgandharvān koṭiśo jaghnebharato vijaye diśām
Translation:
Śatrughna had two sons, named Subāhu and Śrutasena. When Lord Bharata went to conquer all directions, He had to kill many millions of Gandharvas, who are generally pretenders. Taking all their wealth, He offered it to Lord Rāmacandra. Śatrughna also killed a Rākṣasa named Lavaṇa, who was the son of Madhu Rākṣasa. Thus He established in the great forest known as Madhuvana the town known as Mathurā.