The Left group, later called Historical Left by historians to distinguish it from the left-wing groups of the 20th century, was a liberal and reformist parliamentary group in Italy during the second half of the 19th century. The members of the Left were also known as Democrats or Ministerials. The Left was the dominant political group in the Kingdom of Italy from the 1870s until its dissolution in the early 1910s.

The Right group, later called Historical Right by historians to distinguish it from the right-wing groups of the 20th century, was an Italian conservative parliamentary group during the second half of the 19th century. After 1876, the Historical Right constituted the Constitutional opposition toward the left governments. It originated in the convergence of the most liberal faction of the moderate right and the moderate wing of the democratic left. The party included men from heterogeneous cultural, class, and ideological backgrounds, ranging from British-American individualist liberalism to Neo-Hegelian liberalism as well as liberal-conservatives, from strict secularists to more religiously-oriented reformists. Few prime ministers after 1852 were party men; instead they accepted support where they could find it, and even the governments of the Historical Right during the 1860s included leftists in some capacity.