At the beginning of the 19th century, Portugal was in the throes of a civil war over the royal succession, known as the War of the Two Brothers (1828-1834). Prince Miguel organized a revolt against the constitutional order; his brother Pedro, who was crowned as the first emperor of independent Brazil, was the leader of the liberal fraction. Porto was the center of Portuguese progressives, and it endured a long military siege by the royalist forces between 1832 and 1833. In 1832, during a military siege of Porto, a gigantic fire destroyed the St. Francis convent, which dated back to the 13th century. The people of Porto fought bravely to support the Constitutional Charter, and their sacrifice made the victory of the liberal cause possible. Years after the siege of Porto, Queen Mary II, Pedro's daughter, donated the St. Francis convent's ruins to the city's merchants, who decided to build the Palacio to host commercial exchange and a Court of First Instance.