As king, Denis travelled around the country to resolve various problems. He ordered the construction of numerous castles, created new towns, and granted the privileges due cities to several others. He declared in 1290 that 'the language of the people' was to become the language of the state, and officially known as Portuguese. Denis also decreed that Portuguese replace Latin as the language of the law courts in his kingdom. His wife Elizabeth donated much of the large income generated by her lands and properties to charities, inspiring Denis to help improve the life of the poor and found several social institutions. The frequent procedural issues that arose when he issued his decrees increasingly occupied Denis in his quest to frame the common law as being within the scope of the crown's jurisdiction, and in exercising royal power in the realm. The restrictions he placed on the actions of "alvazis" (local council officials), judges, as well as proctors and advocates in the courts, show that a merely nominal power of the monarchy over all the inhabitants of the kingdom, as was typical in the Middle Ages, was not compatible with his effort to assert a royal prerogative to scrutinise legal procedures, or moralise on the exercise of justice. The appointment of magistrates clearly marks the start of the process of the crown claiming territorial jurisdiction, thus expanding the royal domain, along with the growing importance of Lisbon as the nation's de facto capital. The preference for Lisbon as a venue of the royal court was accentuated during Denis's long reign. There was as yet no official capital of the country, but Lisbon's location, as well as its advanced urban, economic and commercial development, made the city the most viable choice for a national centre of administration. Its geographical situation between the ancient divisions of the country, i.e., the north and the south, enhanced Lisbon's status as the most practical centre for an emergent united Portuguese nation, the south now receiving as much royal attention as the north and becoming the residence of the monarchy. Their different characters created a realm where the two regions complemented each other. The great manors were closer together in the north, and the vast dominions conquered from the Muslims in the south, as well as the large areas of unclaimed land there, expanded the domain of the crown, and much of the territory of the extreme south came under the control of the military orders. Denis promoted development of the rural infrastructure, earning the nickname of "the Farmer" ("o Lavrador"). He redistributed land, founded agricultural schools to improve farming techniques, and took a personal interest in the expansion of exports.