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Afonso III of Portugal

1210 – 1279

King of Portugal

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About Afonso III of Portugal

Lived 1210 – 1279 (aged 68). Afonso III of Portugal was a monarch.

Afonso III (; 5 May 1210 – 16 February 1279), called the Boulonnais (Port. o Bolonhês), was King of Portugal and the first to use the title King of Portugal and the Algarve, from 1249. He was the second son of King Afonso II of Portugal and Urraca of Castile; he succeeded his brother, King Sancho II of Portugal, who died on 4 January 1248.

Early life Afonso was born in Coimbra. As the second son of King Afonso II of Portugal, he was not expected to inherit the throne, which was destined to go to his elder brother Sancho.

He lived mostly in France, where he married Countess Matilda II of Boulogne in 1238, thereby becoming count of Boulogne, Mortain, Aumale and Dammartin-en-Goële jure uxoris.

Reign

In 1245, conflicts between his brother, the king, and the church became unbearable. Pope Innocent IV ordered Sancho II to be removed from the throne and to be replaced by the Count of Boulogne. Afonso did not refuse the papal order and consequently marched to Portugal. Since Sancho was not a popular king the order was not hard to enforce, and he fled into exile to Toledo, Castile, where he died on 4 January 1248. Until his brother's death and his own eventual coronation, Afonso retained and used the title of Visitador, Curador e Defensor do Reino (Overseer, Curator and Defender of the Kingdom).

In order to ascend the throne Afonso abdicated his rights to the county of Boulogne in 1248. In 1253, he divorced Matilda in order to marry Beatrice of Castile, illegitimate daughter of Alfonso X, King of Castile, and Mayor Guillén de Guzmán.

Determined not to make the same mistakes as his brother, Afonso III paid special attention to what the middle class, composed of merchants and small land owners, had to say. In 1254, in the city of Leiria, he held the first session of the Cortes, a general assembly comprising the nobility, the middle class and representatives of all municipalities. He also made laws intended to restrain the upper classes from abusing the least favored part of the population. Remembered as a notable administrator, Afonso III founded several towns, granted the title of city to many others and reorganized public administration.

Afonso showed extraordinary vision for the time. Progressive measures taken during his kingship include: representatives of the commons, besides the nobility and clergy, were involved in governance; the end of preventive arrests such that henceforward all arrests had to be first presented to a judge to determine the detention measure; and fiscal innovation, such as negotiating extraordinary taxes with the mercantile classes and direct taxation of the Church, rather than debasement of the coinage. These may have led to his excommunication by the Holy See and possibly precipitated his death, and his son Denis's premature rise to the throne at only 18 years old.

Secure on the throne, Afonso III then proceeded to make war with the Muslim communities that still thrived in the south. In his reign the Algarve became part of the kingdom, following the capture of Faro.

Final years and death Following his success against the Moors, Afonso III had to deal with a political situation concerning the country's borders with Castile. The neighbouring kingdom considered that the newly acquired lands of the Algarve should be Castilian, not Portuguese, which led to a series of wars between the two kingdoms. Finally, in 1267, the Treaty of Badajoz was signed in Badajoz, determining that the southern border between Castile and Portugal should be the River Guadiana, as it is today.

Afonso died in Alcobaça, Coimbra or Lisbon, aged 68.

Marriages and descendants Afonso's first wife was Matilda II, Countess of Boulogne, daughter of Renaud, Count of Dammartin, and Ida, Countess of Boulogne. They had no surviving children. He divorced Matilda in 1253 and, in the same year, married Beatrice of Castile, illegitimate daughter of Alfonso X, King of Castile, and Mayor Guillén de Guzmán.

NameBirthDeathNotesBy Matilda II of Boulogne (–1262; married in 1238)By Beatrice of Castile (1242–1303; married in 1253)Blanche 25 February 1259 17 April 1321Lady of Las HuelgasDenis 9 October 1261 7 January 1325Succeeded him as Denis, 6th King of Portugal. Married Infanta Elizabeth of Aragon.Afonso 8 February 1263 2 November 1312Lord of Portalegre. Married Infanta Violante Manuel (daughter of Manuel of Castile).Sancha 2 February 1264 Maria 1265 Natural son; Married to D. Maria Pais Ribeira, Lady of the House of Sousa.By Elvira Esteves (?-?)Leonor Afonso (nun) ?c. 1302 Natural daughter; Nun in the Monastery of Santa Clara of Santarém.Other natural offspringFernando Afonso??Natural son; Knight of the Order of the hospital.Gil Afonso1250 31 December 1346Natural son; Knight of the Order of the hospital.Rodrigo Afonsob. 1258b. 12 May 1272Natural son; Prior of the city of Santarém.Leonor Afonso?26 February 1291 Natural daughter. Married twice: 1st to D. Estevão Anes de Sousa (without issue), 2nd to D. Gonçalo Garcia de Sousa, Count of Neiva (without issue).Urraca Afonso (nun)? 4 November 1281 Natural daughter; Nun in the Monastery of Lorvão.

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Important facts

Birth century
Occupation
Nationality
Kingdom of Portugal
Positions held
Monarch of Portugal, Count of Boulogne
Also known as
Afonso III

Family & relationships

Spouse
Beatrice of Castile (1242–1303)
Spouse
Matilda II, Countess of Boulogne
Child
Afonso of Portugal, Lord of Portalegre
Child
Blanche of Portugal (1259–1321)
Child
Denis of Portugal
Child
Maria of Portugal (nun)
Child
Martim Afonso Chichorro
Child
Sancha of Portugal (born 1264)
Child
Urraca Afonso
Parent
Afonso II of Portugal
Parent
Urraca of Castile, Queen of Portugal

People in Afonso III of Portugal's life

Named in this biography and alive at the same time

Contemporaries

People whose lives overlapped Afonso III of Portugal's

Frequently asked questions

Who was Afonso III of Portugal?

King of Portugal

When was Afonso III of Portugal born?

Afonso III of Portugal was born on 5 May 1210 in Coimbra.

When did Afonso III of Portugal die?

Afonso III of Portugal died on 16 February 1279 in Lisbon, Alcobaça.

What was Afonso III of Portugal's occupation?

Afonso III of Portugal was a monarch.

What nationality was Afonso III of Portugal?

Afonso III of Portugal's recorded nationality: Kingdom of Portugal.

Sources & further reading

· Wikipedia: Afonso III of Portugal

· Wikidata: Q295850

· DBpedia: Afonso III of Portugal

Cite this page

APA: Biography.guide. (2026). Afonso III of Portugal. https://biography.guide/afonso-iii-of-portugal/

MLA: "Afonso III of Portugal." Biography.guide, https://biography.guide/afonso-iii-of-portugal/.

Chicago: "Afonso III of Portugal." Biography.guide. https://biography.guide/afonso-iii-of-portugal/.

Data last updated: 2026-09-21 · Spot an error? Report a correction.

Portrait: Wikimedia Commons · author & licence

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