Bienio progresista revolutionary coup in Spain

Background. By mid-1854, the Moderate regime under the Count of San Luis was in a critical state due to corruption and instability. Street protests had spread from Zaragoza to other parts of Spain. The political system, dominated by the Moderate Party since 1843, faced growing opposition from progressives who sought institutional modernization and an end to the existing political stagnation.

The Vicalvarada. On 28 June 1854, Leopoldo O'Donnell, a moderate general, led a military pronunciamiento at Vicálvaro, southeast of Madrid. He confronted troops loyal to the government, demanding a new administration to address corruption. Although the initial military result was mixed, O'Donnell sought civilian support to broaden the movement's appeal beyond the moderate faction.

Manifesto and Government. To appeal to progressives, O'Donnell issued the Manifesto of Manzanares on 7 July 1854, drafted by Antonio Cánovas del Castillo. This document promised liberal reforms. Consequently, Baldomero Espartero was called to government, becoming Prime Minister on 19 July 1854, thus opening the two-year period known as the Bienio progresista.