Alfonso III (1265 – 18 June 1291), called the Liberal (el Liberal) or the Free (also "the Frank," from el Franc), was the King of Aragon and Count of Barcelona (as Alfons II) from 1285. He conquered the Kingdom of Majorca between his succession and 1287.
He was a son of Peter III of Aragon and his Queen consort Constantia of Sicily, daughter and heiress of Manfred of Sicily. His maternal grandmother Beatrice of Savoy was a daughter of Amadeus IV of Savoy and Anne of Burgundy.
Soon after assuming the throne, he conducted a campaign to reincorporate the Balearic Islands into the Kingdom of Aragon - which had been lost due to the division of the kingdom by his grandfather, James I of Aragon. Thus in 1285 he declared war on his uncle, James II of Majorca, and conquered both Majorca (1285) and Ibiza (1286), effectively reassuming suzerainty over the Kingdom of Majorca. He followed this with the conquest of Minorca - until then, an autonomous Muslim state (Manûrqa) under the Kingdom of Majorca - on 17 January 1287, the anniversary of which now serves as Minorca's national holiday.
He initially sought to maintain the Aragonese control over Sicily early in his reign by supporting the claims to island of his brother, James II of Aragon. However, he later pressed his brother to retract the claims and instead supported claim from the Papal States.
His reign was marred by a constitutional struggle with the Aragonese nobles, which eventually culminated in the articles of the Union of Aragon - the so called "Magna Carta of Aragon", which devolved several key royal powers into the hands of lesser nobles. His inability to resist the demands of his nobles was to leave a heritage of disunity in Aragon and further dissent amongst the nobility, who increasingly saw little reason to respect the throne, and brought the Kingdom of Aragon close to anarchy.
He died at the age of 27 in 1291, and buried in Barcelona. He bore no children, despite being married on August 15, 1290 to Princess Eleanor of England, daughter of Edward I of England and Princess Eleanor of Castile.
Dante Alighieri, in the Divine Comedy, recounts that he saw Alfonso's spirit seated outside the gates of Purgatory with the other monarchs whom Dante blamed for the chaotic political state of Europe during the 13th century.