At the beginning of the 13^th century, the Crown of Aragon focused its expansion policy on the Mediterranean. The conquests of Majorca and Valencia by James I were continued by Peter the Great, who annexed Sicily, and his successors. Catalan hegemony and the struggle to rule Sardinia and Naples caused conflicts with France, the Genoese Republic and the Papacy.

“Consulates of the Sea” were set up in the main Mediterranean ports to deal with maritime and commercial issues. In the eastern Mediterranean the Crown of Aragon did not manage to displace the Republic of Venice, despite taking control of the duchies of Athens and Neopatria. From the 14^th and 15^th centuries onwards, internal crises and social conflicts weakened the Crown and put an end to its hegemony.

The growing complexity of Low Medieval society meant that, throughout the 13^th and 14^th centuries, Catalonia was provided with institutions of government: the Corts (parliament) and the Generalitat (administration). At a time when monarchies were becoming stronger and tending towards authoritarianism, in the Principality and other Crown territories the institutionalised practice of pacts and consensus as the basic foundation of royal government became predominant.

The Corts included the three main estates: the ecclesiastical branch, the nobility and the popular classes, representing the towns and cities within the royal jurisdiction. The peasants, who formed the largest part of the population, had no direct presence. Consensus took the form of drawing up constitutions or laws. Meanwhile, the Generalitat, the permanent representative of the estates, oversaw compliance with the agreements.

From the 13^th century onwards, the increase in agricultural production and the development of trade drove population and economic growth. The cities became manufacturing and trading centres and the kings encouraged them, finding that they provided reliable support against the upper ranks of the feudal nobility as they flourished.

The dynamism of the urban centres was shown in their desire to achieve greater self-government, as with the establishment of the Council of One Hundred in Barcelona and the construction of spectacular cathedrals, churches, markets and palaces. Gothic art, in all its splendour, spread through the cities of Barcelona, Majorca, Perpignan and Valencia.

In the Low Middle Ages, Catalan became a fully developed written language. Literature was particularly outstanding, with figures like Ramon Llull, Jordi de Sant Jordi and Ausiàs March, and works like Tirant lo Blanch became universally known. The first universities were founded and advanced scientific and technical practices were developed locally.

Catalan medicine achieved great prestige and Arnaldus de Villa Nova became physician to three kings and three popes. The cartographers Abraham and Jehuda Cresques and their Atlas Català of 1375 were also important figures. Drawn with surprising precision, the most important mapamundi of its time included India and China and summarised the concerns of a rapidly expanding world.

After the mid-14^th century, Catalonia underwent strong political and social convulsions, as well as a considerable fall in population and economic recession. The crisis, beginning during the reign of Peter the Ceremonious, continued in the reigns of the first kings of the Trastamara dynasty. The Civil War of 1462-1472 pitted the Crown against the country’s institutions and afflicted a territory already been decimated by epidemics.

Feudal oppression led to the peasants’ revolt which went on during the second half of the 15^th century and did not end until the Arbitral Decision of Guadalupe (1486), which abolished what it described as the lords’ “evil customs”. At the end of the 15^th century, the population reached a historic low: 250,000 inhabitants. The Mediterranean became less important compared to the new ocean routes and Catalonia was left on the periphery of the new trade highways.