: boulai, βουλαί) was a council (βουλευταί, bouleutai) appointed to run daily affairs of the city.
Originally a council of nobles advising a king, boulai evolved according to the constitution of the city: In oligarchies boule positions might have been hereditary, while in democracies members were typically chosen by lot and served for one year.
In strengthening the common Athenian identity Cleisthenes devised an artificial political division of Athens into ten tribes.
Each of the ten tribes supplied 50 men to the council with each of the 50 adhering from its constituting demes and distributed according to the size of their population.
[3] Membership was restricted at this time to the top three of the original four property classes (the pentacosiomedimni, hippeis and zeugitae, but not the thetes) and to citizens over the age of thirty.
Three of the main mechanisms in place were; monitoring by other governing institutions including the assembly (ekklesia) and the courts, the required rendering of a full account of the work undertaken upon leaving the council and not least the ability of the general citizenry and fellow council members to charge individual members with a vote of no confidence.
[2][5] After the reforms of Ephialtes and Pericles in the mid-5th century BC, the boule took on many of the administrative and judicial functions of the Areopagus, which retained its traditional right to try homicide cases.
It heard some cases of impeachment of public officials for high crimes and mismanagement or serious dereliction of duties.
The boule was considered the cornerstone of the democratic constitution, providing a locus for day-to-day activities and holding together the many disparate administrative functions of the government.