Dinis of Portugal (in archaic Portuguese: Diniz; in English: Denis), the Farmer (Portuguese: o Lavrador), sixth king of Portugal and Algarve, was born in Lisbon in October 9, 1261 and died in January 7, 1325 in Santarém. He was the eldest son of Afonso III of Portugal by his second wife, princess Beatrice of Castile. Dinis succeeded his father in 1279.

As heir to the throne prince Dinis was summoned by his father (Afonso III) to share government responsibilities. At the time of his accession to the throne, Portugal was again in diplomatic conflicts with the Catholic church. Dinis signed a favouring agreement with the pope and swore to protect the Church's interests in Portugal. Due to this, he granted asylum to the Templar knights persecuted in France and created the Order of Christ, designed to be a continuation of the Order of the Temple.

With the Reconquista completed and the Portuguese territory freed from Moorish occupation, Dinis was essentially an administrative king, not a military one. However, a short war between Castile and Portugal broke during his reign, for the possession of the town of Serpa and Moura. After this, Dinis avoided war: he was a notably peace-loving monarch during a tempestuous time in European history. With Portugal finally recognized as an independent country by his neighbours, Dinis signed a border pact with Ferdinand IV of Castile (1297) which has endured to the present day.

Dinis main priority of government was the organization of the country. He pursued his father's policies on legislation and centralization of power. Dinis promulgated the nucleus of a Portuguese civil and criminal law code, protecting the lower classes from abuse and extortion. As king, he travelled around the country, correcting unjust situations and resolving problems. He ordered the construction of numerous castles, created new towns, and granted privileges due cities to several others. With his wife, princess Isabella of Aragon, Dinis worked to improve the life of the poor and founded several social institutions.
Always concerned with the country's infrastructure, Dinis ordered the exploration of mines of copper, silver, tin and iron and organized the export of excess production to other European countries. The first Portuguese commercial agreement was signed with England in 1308. Dinis effectively founded the Portuguese navy under command of a Genoese admiral and ordered the construction of several docks.

His main concern was the redevelopment and promotion of rural infrastructure, hence the nickname “the Farmer”. Dinis redistributed the land, promoted agriculture, organized communities of farmers and took personal interest in the development of exports. He instituted regular markets in a number of towns and regulated their activities. One of his main achievements was the protection of agricultural lands from advancing coastal sands, by ordering the planting of a pine forest near Leiria. This forest still exists as one of the most important of Portugal and is known as the Pinhal de Leiria.

Culture was another interest of King Dinis. He had a fondness for literature and wrote several books himself, with topics ranging from administration to hunting, science and poetry. In his days, Lisbon was one of Europe's centers of culture and knowledge. The University of Coimbra was founded by his decree Magna Charta Priveligiorum.

The latest part of his peaceful reign was nevertheless marked by internal conflicts. The contenders were his two sons: Afonso the legitimate heir, and Afonso Sanches his natural son, who quarrelled frequently among themselves for royal favour. At the time of Dinis death in 1325 he had placed Portugal on an equal footing with the other Iberian Kingdoms.