In the history of Spain, the bienio progresista was the two-year period from July 1854 to July 1856, during which the Progressive Party attempted to reform the political system of the reign of Isabella II, which had been dominated by the Moderate Party since 1843 in the so-called década moderada. The Progressives were exaltados or veinteañistas, advocates of radical liberalism, in contrast to the conservative liberalism of the doceañistas or Moderates.