General Military Council

Cossack Rada (Ukrainian: Козацька рада, Kozats'ka Rada) or General Military Council was a general Cossack assembly (council) often military in nature.

Originally established at the Zaporizhian Sich, the rada (council) was an institution of Cossack administration in Ukraine from the 16th to the 18th century. With the establishment of the Hetman state in 1648, it was officially known as the General Military Council until 1750.

One of the most famous of those councils was the Chorna rada of 1663, described in the novel Chorna Rada (The Black Council) by Panteleimon Kulish. At that council the Hetmanate faction of Khmelnytsky were deposed from the government and replaced by Bryukhovetsky, the first hetman who became the Russian boyar.

...
Wikipedia