The Ethir Gwathló (S. "Mouth [of the] Greyflood") had once been a Cardolanian principality. It had included a narrow strip of floodplain along the great river and a goodly expanse of treeless grassland inland, but the portion of it within the bounds of Cardolan became a short-lived military march. The Princes of Ethir Gwathló were a corrupt line, its Ernil commonly an absent ruler, usually living in luxury in Tharbad and concerned only with the prompt arrival of his taxes. Mainly concerned with their tolls on traffic on the river, the last Princes of Ethir Gwathló had allowed a few Dunman tribes to settle in their territory for vague and rarely fulfilled promises of tribute. The population grew greatly as times got rougher, swelled by refugees from the north and east. The emergent culture of the Dynion of Saerlann had little use for their absentee landlord, and generally cooperated when the usurper Gordaig Trollbane drove out the forces of the last Prince and proclaimed himself a King. So the new Kingdom of Saerlann became the first successor state of the Principality of Ethir Gwathló and its capital, the port formerly called Mistalondë or Lond Gwathló, was renamed Sunthra Unsar in honor of the first King's father.