In Portugal, the country was in effective civil war since 1826, when "usurper-king" Miguel I of Portugal and his elder brother Pedro IV of Portugal battled, until 1834. Sebastian's mother remarried two decades later, in 1838, her uncle, DonCarlos, Count of Molina, the first Carlist pretender of Spain. Teresa had been a Carlist supporter since the succession dispute started in 1833, and spent her time in the Carlist camp, usually in northern Spain. Sebastian participated in the second siege of Bilbao and became commander of the Carlist Army of the North from December 30, 1836. He won the Battle of Oriamendi against the British Legion under George de Lacy Evans. Then he led the failed Royal Expedition against Madrid and was sacked upon its return to the north in late 1837.
Titles
On January 15, 1837, during the First Carlist War, the then 23-year-old Sebastian was excluded, by law of the Cortes, ratified by royal decree of Queen Regent Maria Christina, from the Spanish succession, on the grounds that he had joined Don Carlos' rebellion against Isabella II of Spain. Sebastian was also declared to be stripped of his Spanish titles and status as a dynast. The same exclusion was legislated against Sebastian's mother and uncle, the deposed Miguel I of Portugal, as well as Don Carlos and his sons,. In 1859 Sebastian was restored to his Spanish titles, in conjunction with his second marriage. He returned to Spain from Naples where he had lived since the end of the war in 1839.
Marriage and family
Sebastian first wed his cousin Princess Maria Amalia of Bourbon-Two Sicilies, but the marriage, which lasted several decades, remained childless. When widowed at the age of 50 he remarried, on 19 November 1860, his cousin Infanta Maria Cristina of Spain, the niece of his first wife, and two decades his junior. Their three sons, all Spanish dynasts until their marriages, were each granted dukedoms. Their children, reckoned members of the House of Bourbon-Braganza, were:
Francisco, Duke of Marchena, wed María del Pilar de Muguiro y Beruete, Duchess of Villafranca.
Luis, Duke of Ansola, wed María Ana Bernaldo de Quirós y Muñoz, Marquise of Atarfe.
Don Alfonso de Borbón-Braganza y Borbón.
Don Gabriel de Borbón-Braganza y Borbón.
The last head of one of these branches, the Duke of Hernani, adopted in the 1970s their distant cousin, Infanta Margarita of Spain, Duchess of Soria, who thus became the next and current Duchess of Hernani. After the overthrow of Isabella II of Spain in 1868 Sebastian moved to Pau, where he tried to reconcile the Carlist and Isabeline branches of the House of Bourbon, without success.