The extent of the violence was such that prisoners held by the town council had to be released when an angry mob threatened to storm its headquarters, the Townhouse.
Despite the violent scenes, which began in Schoolhill and quickly moved through the city centre, the episode has largely been eradicated from the city’s history books.
Dr Andrew MacKillop, a senior lecturer in history at the University of Aberdeen, said the events were a dark chapter in the history of a city known for its conservative nature and advocacy of peaceful reform.
Dr MacKillop said divisions among the city’s different trades had built over calls for electoral reform, with the high feelings set against the background of Britain’s defeat in the American Revolutionary War.
This led to pressure for greater national and local government accountability and in Scotland a national campaign for reform of the burgh electoral system was well underway by 1784, with Aberdeen at the forefront of the movement.
The Incorporated Trades were courted for support by the Aberdeen Burgesses, who were pressuring the council for greater transparency of taxes and how councillors were elected.
This, says Dr Mackillop, signalled the beginning of tensions with trades pitted against trades.
Weavers and Taylors developed a strong reformist agenda but coopers were at odds with their position - with dire consequences for the city.
Violence first erupted when a group of wrights were set upon by a band of coopers, with the mood further darkening overnight.
By the following morning a crowd of 40 to 50 wrights and their supporters gathered on Shiprow and a series of street brawls followed. Wrights moved through the city attacking any cooper they met, with numbers swelling across the course of the day.
Dr MacKillop said: “The brawls moved across the city Until the authorities finally intervened as the crowd moved up Marischal Street towards the Castlegate.”
Soldiers moved in and three of the ringleaders were arrested.
More violent scenes followed that night as supporters of the arrested men surrounded the tolbooth, a former prison, with stones being lopped through the windows as they demanded their release.
A crowd of “many thousand” gathered with the provost warning that they risked being fired upon by soldiers.
Dr MacKillop said: “Unsurprisingly, the arrested men were given back to their supporters while councillors surreptitiously sought refuge elsewhere.
“The provost was followed back to his house, which the crowd threatened to destroy,” he added.
“Aberdeen’s reputation as a well governed, orderly burgh was ruined. The council was humiliated by its own populace and reform supporters among the burgesses and trades implicated in violent crowd action.
“The result was an obvious desire on the part of all concerned to draw a line under the whole affair.”
The trial of a small number of rioters in July 1786 led to a “surprising number of not guilty verdicts and limited fines for those deemed guilty.
Dr MacKillop added: “This low key response hastened the process by which the riot, despite its violent nature and two day duration, was conveniently forgotten.
“As a result is remains an almost wholly unknown aspect of Aberdeen history.”
The Aberdeen Riots of October 1785 will be discussed at Aberdeen University’s May Festival on Friday May 27 from 11.30am to 12.30pm.
Tickets are free of charge but must be reserved at www.abdn.ac.uk/mayfestival.