We know Karna's foster father Adhiratha, a charioteer. He was a Suta which is defined to be descendant of Kshatriya father and Brahmana mother (as per Manusmriti).
But do we have any information on Adhiratha's lineage. As per Srimad Bhagvatam, Adhiratha's was a direct descendant of King Rompada, friend of King Dashratha.
By the mercy of Ṛṣyaśṛṅga, Romapāda had a son named Caturaṅga. The son of Caturaṅga was Pṛthulākṣa, who had three sons — Bṛhadratha, Bṛhatkarmā and Bṛhadbhānu. From Bṛhadratha came a son named Bṛhadmanā, whose sons and grandsons in succession were Jayadratha, Vijaya, Dhṛti, Dhṛtavrata, Satkarmā and Adhiratha. Adhiratha accepted the son rejected by Kuntī, namely Karṇa, and Karṇa’s son was Vṛṣasena.
The exact verses are from 9-23-7 to 9-23-12.
So do scriptures describe any events wherein King Rompada descendants lost their kingdom, and become charioteers.