Maria of Portugal (; 6 April 1342, in Évora, Kingdom of Portugal – 1377, in Aveiro, Kingdom of Portugal or Genoa, Republic of Genoa, Liguria, Italy) was a Portuguese infanta (princess) member of the House of Burgundy and by marriage Marchioness of Tortosa and Lady of Albarracín. She was the eldest child and daughter of infante Pedro of Portugal (who became King in 1357) and his first wife Constanza Manuel. Her parents' marriage produced four children, but only infanta Maria and her younger brother, the future King Fernando I of Portugal survive adulthood; from her father's relationship (or second marriage) with Inês de Castro and later affair with Teresa Lourenço, she had several half-siblings, including Beatriz, Countess consort of Alburquerque and João of Aviz, who became King of Portugal in 1385 and founder of the House of Aviz, who ruled the Kingdom of Portugal until 1580. Life On 3 February 1354, the 11-years-old infanta Maria married her distant cousin infante Fernando of Aragon, Marquis of Tortosa and Lord of Albarracín (son of King Alfonso IV of Aragon and his second wife, Eleanor of Castile). This marriage was arranged by her grandfather, King Afonso IV of Portugal, to strengthen the alliance between the Kingdom of Portugal and the Crown of Aragon. About this union, from which there was no offspring, historian Jerónimo Zurita y Castro mentions that "the King of Aragon showed much discontent and regret", since it meant that from that moment the Kingdom of Portugal took part in the conflict between Aragon and Castile. King Afonso IV gave to his granddaughter as a dowry the villages of Ilhavo, Milho, Arcos, Crastadaes, Quintella, Carvalhaes, Ferreiros, and houses in Espinel, Cea, Ponte de Almeara and Avellãas, with all its terms and rights, civil and criminal jurisdiction. During the War of the two Pedros between King Pedro IV of Aragon and his cousin King Pedro I of Castile (nicknamed the Cruel), infante Fernando, who aspired to the throne of the latter, turned out to be a completely annoying ally for his half-brother Pedro IV, who, remembering his previous participation in the revolt of the Kingdom of Valencia, had him assassinated on 16 July 1363. The now widowed infanta Maria sees how her brother-in-law seized her deceased husband's domains (Tortosa, Albarracín, Fraga and other places) and forbade her to return to Portugal, as was her intention, until she renounced all the property that