One of Gramsci’s very important theoretical concepts is historical bloc. On the one hand, the concept of historical bloc, in Prison Notebooks, is referred to a unity between the structure and the superstructure. On the other hand, Gramsci uses the concept as a homogeneous politico-economic alliance which does not have internal contradictions. Stephen Gill argues that a historical bloc is a process which is initiated by a conscious social force which intends to establish a new hegemony.
“An historical bloc refers to an historical congruence between material forces, institutions and ideologies, or broadly, an alliance of different class forces politically organized around a set of hegemonic ideas that gave strategic direction and coherence to its constituent elements. Moreover, for a new historical bloc to emerge, its leaders must engage in conscious planned struggle. Any new historical bloc must have not only power within the civil society and economy, it also needs persuasive ideas, arguments and initiatives that build on, catalyze and develop its political networks and organization – not political parties such.”
The concept of historical bloc is important because it refers to a moment during the process of change which indicates that a political party has been built, and it is seeking to establish a hegemony. To do that, Gramsci argues that this social class, through its political party, has to organize other social classes and political parties as well to take part in their wider political, economical alliance, which in theory by Gramsci called as “historical bloc”. In that process, the organic intellectuals of the political party and the social class also play a fundamental role in producing the persuasive ideas and arguments needed in convincing other classes to be a part of their historical bloc, thus their upcoming hegemony.
However, as Anne Showstack Sassoon rightly points out, “an historical bloc is not to be reduced to a mere political alliance since it assumes a complex construction within which there can be sub-blocs such as, for example, an agrarian bloc, a complex formation of its own right, and an industrial bloc, each of these containing different elements and potential contradictions. The historical bloc can produce various political blocs made up of different combinations of political allies which none the less maintain the general configuration of the fundamental historical bloc.”
As previously mentioned, the political party, the historical bloc and the hegemony are interconnected instruments in Gramsci’s thought through which a socio-political change can be realized. As Sassoon explains, “the historical bloc in implying necessarily the existence of hegemony also implies that in order to create a new historical bloc alternative to the existing one, the new, progressive class must create its own hegemonic apparatuses. The way in which the working class is able to do this, according to Gramsci, is through the party.”
 See Gramsci, Selections from the Prison Notebooks, ibid., p. 137. Also see p. 366. “Structures and superstructures form an historical bloc.”
 Ibid. p. 168.
 Gill, Stephen, Power and Resistance in the New World Order, Palgrave, Macmillan – 2002, p. 58.
 Anne Showstack Sassoon, Gramsci’s Politics, Minneapolis: University of Minnesota Press, 1987, p. 121.
 Ibid., pp. 123-124.