In March 1820, Beresford went to Brazil to persuade the king to return to the throne. His departure allowed the influence of the liberals to grow within the army, which had emerged from the Peninsular Wars as Portugal's strongest institution. On August 24, 1820, regiments in Porto revolted and established a provisional junta that assumed the government of Portugal until a cortes could be convoked to write a constitution. The regency was bypassed because it was unable to cope with Portugal's financial crisis, and Beresford was not allowed to enter the country when he returned from Brazil.
In December 1820, indirect elections were held for a constitutional cortes, which convened in January 1821. The deputies were mostly constitutional monarchists. They elected a regency to replace the provisional junta, abolished seigniorial rights and the Inquisition, and, on September 23, approved a constitution. At the same time, João VI decided to return to Portugal, leaving his son Pedro in Brazil. Upon his arrival in Lisbon, João swore an oath to uphold the new constitution.
Portugese Military Revolt 1820...In 1820, when a military revolt in Spain forced the revived absolutist regime of Fer-nando VII (1784-1833) to restore the liberal constitution of 1812, the Portuguese military followed suit by expelling the British officers and forming revolutionary juntas. The military petitioned the king's return and summoned a Côrtes (the Portuguese Parliament), the first since 1697 when the crown had dispensed with such bodies.
Unable to do more, João pardoned the juntas' usurpation of his prerogative to summon a Côrtes and acknowledged that a Côrtes could be useful in making proposals to him on how best to govern the United Kingdom.
In the timeframe of the "Portugese Civil War 1820-1834" in Dunnigan and Martel's How to Stop a Warlist.