Portuguese House of Burgundy in the context of Theresa of Portugal, Countess of Flanders

The Kingdom of Portugal was a monarchy in the western Iberian Peninsula and the predecessor of the modern Portuguese Republic. Existing to various extents between the mid-12th century and the early 20th century, it was also known as the Kingdom of Portugal and the Algarves after 1471, and was the main constituent of the United Kingdom of Portugal, Brazil and the Algarves, which existed between 1815 and 1822. It coexisted with the Portuguese Empire, the realm's overseas colonies.

The nucleus of the Portuguese state was the County of Portugal, established in the 9th century as part of the Reconquista by Vímara Peres, a vassal of the King of Asturias. The county became part of the Kingdom of León in 1097, and the Counts of Portugal established themselves as rulers of an independent kingdom in the 12th century, following the Battle of São Mamede. The kingdom was ruled by the Afonsine Dynasty until the 1383–85 Crisis, after which the monarchy passed to the House of Aviz.

The House of Aviz (Portuguese: Casa de Avis [ɐˈviʃ]), also known as the Joanine Dynasty (Dinastia Joanina), was a dynasty of Portuguese origin which flourished during the Renaissance and the period of the Portuguese discoveries, when Portugal expanded its power globally.

The house was founded by King John I of Portugal, Grand-Master of the Order of Aviz and illegitimate son of King Pedro I (of the Portuguese House of Burgundy), who ascended to the throne after successfully pressing his claim during the 1383–1385 Portuguese interregnum. Aviz monarchs would rule Portugal through the Age of Discovery, establishing Portugal as a global power following the creation of the Portuguese Empire. In 1494, Pope Alexander VI divided the world under the dominion of Portugal and Spain with the Treaty of Tordesillas.

Póvoa de Varzim (European Portuguese pronunciation: [ˈpɔvu.ɐ ðɨ vɐɾˈzĩ] ) is a Portuguese resort city in Northern Portugal and sub-region of Greater Porto, 30 km (18.6 mi) from its city centre. It sits in a sandy coastal plain, a cuspate foreland, halfway between the Minho and Douro rivers. In 2001, there were 63,470 inhabitants, with 42,396 living in the city proper. The city expanded southwards, to Vila do Conde, and there are about 100,000 inhabitants in the urban area alone. It is the seventh-largest urban agglomeration in Portugal and the third largest in Northern Portugal.

Permanent settlement in Póvoa de Varzim dates back to around four to six thousand years ago. Around 900 BC, unrest in the region led to the establishment of Cividade de Terroso, a fortified city, which developed maritime trade routes with the civilizations of classical antiquity. Modern Póvoa de Varzim emerged after the conquest by the Roman Republic of the city by 138 BC; fishing and fish processing units soon developed, which became the foundations of the local economy. By the 11th century, the fishing industry and fertile farmlands were the economic base of a feudal lordship and Varzim was fiercely disputed between the local overlords and the early Portuguese kings, which resulted in the establishment of the present day's municipality in 1308 and being subjugated to monastic power some years later. Póvoa de Varzim's importance reemerged with the Age of Discovery due to its shipbuilders and merchants proficiency and wealth, who traded around the globe in complex trade routes. By the 17th century, the fish processing industry rebounded and, sometime later, Póvoa became the dominant fishing port in Northern Portugal.

Berengaria of Portugal (Portuguese: Berengária, Danish: Bengjerd; c. 1198 – 27 March 1221) was a Portuguese infanta (princess), who became Queen of Denmark, as the second wife of Valdemar II, from 1214 until her death.

Born into the Portuguese House of Burgundy, she was the daughter of King Sancho I of Portugal and Dulce of Aragon. Likely the youngest of her siblings, she may have been the twin of Branca, and their mother died shortly after their birth. Following the death of her father in 1211, Berengaria became an orphan, and her brother, now King Afonso II, soon sought to curtail his siblings' bequeathed estates. In the ensuing conflicts, Berengaria was initially entrusted to the care of her elder sister Theresa, formerly Queen of León, then a nun at the convent of Lorvão in Penacova. Another brother Ferdinand fled to France, becoming Count of Flanders in 1212, and Berengaria seems to have followed him there or to the court of his overlord, Philip II of France, a cousin of theirs. Seeking to consolidate an anti-French North Sea alliance with King John of England, Emperor Otto IV and others, Ferdinand arranged her marriage to Valdemar II of Denmark, likely facilitated through Valdemar’s sister Ingeborg, the estranged queen of Philip II. The later marriage of Berengaria’s niece Eleanor of Portugal to Valdemar’s eldest son, Valdemar the Young, in 1229 further tightened the dynastic links between the Portuguese and Danish royal houses.

The Military Order of Aviz (Portuguese: Ordem Militar de Avis), known previously to 1910 as the Royal Military Order of Saint Benedict of Aviz (Portuguese: Real Ordem Militar de São Bento de Avis), and before 1789 as the Knights of Saint Benedict of Aviz (Portuguese: Ordem de São Bento de Avis) or Friars of Santa Maria of Évora, is one of the four former ancient Portuguese military orders. It gave its name and coat of arms to the House of Aviz that ruled Portugal between 1385 and 1580. The founding king of House of Aviz, John I of Portugal, was an illegitimate son of a previous king, and thus not a member of his father's Portuguese House of Burgundy; however, John was the grand master of the Order of Aviz, and thus was known as "John of Aviz." Founded in 1146, it is the oldest Portuguese honorific order.

The Kingdom of Portugal was established from the county of Portugal in the 1130s, ruled by the Portuguese House of Burgundy. During most of the 12th and 13th centuries, its history is chiefly that of the gradual reconquest of territory from the various Muslim principalities (taifas) of the period.

This process was essentially complete with the ascension of Afonso III of Portugal, the first to claim the title of King of Portugal and the Algarve. The history of Portugal in the period between the death of Afonso III in 1279 and the beginning of the Portuguese Empire in 1415 includes the 1383–1385 Portuguese interregnum and the subsequent transition from the Portuguese House of Burgundy to the House of Aviz.