Excavations at Cromartie Memorial car park in Dingwall have uncovered remains of a mound which would have served as a gathering place for 11th century nobles and chieftains.
Thought to have been built by the Norse earl Thorfinn the Mighty, the mound would have been sited on a man-made island on the river Peffery.
Thorfinn, who died in 1065, is believed to have laid the foundations of what would later become the royal burgh of Dingwall. Experts say a road, ditch and an aquaduct, known as the Water of Dyke, were also constructed when Thorfinn was in control of Ross-shire and large parts of the north of Scotland.
The parliament, called a Thing, was included in an 18th century plan of the town. Other sites known to have been sited Things in Scotland can also be found in Shetland and Orkney.
Thorfinn's rise to power was aided by his victory in a battle at Torfnes on the south side of the Cromarty Firth, and he grew to become lord of Caithness, Shetland and Orkney.
OJT Heritage and Dingwall History Society were involved in excavating parts of Cromartie Memorial car park, which is on a piece of land known as the Hillyard.
Radio carbon dating of earth samples indicated the mound had been constructed in the estuary of the Peffery around the mid-11th Century.
David MacDonald was commissioned to put together a historical investigative report on the thing site.
Mr MacDonald said: "That dating is consistent with the period in which, following his victory at Torfnes until his death, Earl Thorfinn the Mighty had exercised authority over Ross."