The Roman law exercised a powerful influence in Aragon as elsewhere. Thus freedom of testament was introduced, and primogeniture attained to a predominant place. The guilds did not advance to the point reached in Castile, existing rather for purposes of mutual aid, and lacking the technical regulations of the Castilian guilds. _Catalonia_ [Sidenote: Revolts of the serfs.] There are two prime facts in the social history of Catalonia in this period: the uprising of the serfs; and the outstanding importance of the cities, especially Barcelona. The first marked the decline of the nobility and the appearance of a new social factor; the second indicated the direction which modern social organization was to take. Having lost their political power the nobles concentrated their interest on getting wealth out of their lands, especially through the tributes of their serfs. In this respect they had the enormous advantage of possessing the greater part of Catalan territory.[41] The serfs were subject to a great number of annoying personal services, and (in a typical case) to as many as thirty different tributes, most of them in kind, besides the ordinary rental for the land. They had already won a right to redeem themselves for money, and Juan I, Martín I, and María (the wife and regent of Alfonso V), as well as many jurisconsults, made some more or less ineffectual attempts to better their condition. The plagues which swept Europe in the fourteenth century were a greater aid, since laborers became scarce and therefore more desirable. By the time of Alfonso V the serfs had become sufficiently emboldened to formulate demands, on the threat of a general uprising. Alfonso accepted a sum of money from them, granted what they asked, and then withdrew his promises when the nobles also bribed him. The revolt was delayed, however, to the year 1462 in the next reign, when it formed one of the complications in the wars of Juan II against the deputation of Catalonia and the city of Barcelona. Both sides sought the aid of the serfs, but Juan was able to win them to his support, although their military operations were directed primarily against their own lords. The peace of 1472 did not solve the social question; so there was another uprising in 1475, and it was still going on at Juan’s death, in 1479, being left for solution to the reign of his son, Ferdinand. [Sidenote: Decline of the nobility.] [Sidenote: Persecution of the Jews.]