PSALMS OF THE BRETHREN
Psalms of Single Verses
Translated from the Pali by Mrs. C.A.F. Rhys Davids.
Reborn in this Buddha-age as the son of the rāja of a district, he was unable to maintain his country's independence, and lost his throne. Wandering about the land unhappy, he saw and heard the Exalted One, entered the  Order, and won arahantship. And inveighing in his psalm against worldliness, he thus in divers ways confessed aññā:
 By vain conceits deluded, and their wits
Corrupted by the varied things of sense;
Flushed by their gains, by dearth thereof upset,
They fail to win the concentrated mind.
Maṇḍala-rājā. I would guess from the title 'Circulating-king', that this was a temporary rulership, perhaps subject to periodic election, or subject to the whim of a greater king.