War of the Two Brothers

Portuguese history

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

July 14, 2026

Quick Summary

The War of the Two Brothers, also known as the Liberal Wars, was a conflict in Portuguese history fought between 1828 and 1834. It was a struggle for the Portuguese throne between the absolutist King Michael I and his liberal brother, Pedro IV (who had abdicated the Brazilian throne).

The war began when Michael I, who had been appointed regent, seized the throne and began persecuting liberals. Pedro IV, supported by liberal forces, launched an expedition from Europe to reclaim the throne for his young daughter, Maria II. After a year-long siege in Porto, the liberal forces eventually gained the upper hand, capturing Lisbon and forcing Michael I to capitulate. The conflict ultimately affirmed a constitutional monarchy in Portugal.1

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

2 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

Portugal
The War of the Two Brothers
John VI acknowledged the independence of Brazil in 1825, assuming pro forma the imperial title and then yielding it to Pedro. However, when John died (March 10, 1826), no provision had been made for the succession except that his…
Read More
John VI acknowledged the independence of Brazil in 1825, assuming pro forma the imperial title and then yielding it to Pedro. However, when John died (March 10, 1826), no provision had been made for the succession except that his…
Read More