The economical exceso, Ander feudal rent form, perceptioned on account of judicial, legal and gobernmental prerrogativas, over artisans and tradesmen, adopted the fiscal taxs, royal impositions or towcouncil tax form in the medieval cities. The used systems for the obtaining of the artisan rents, were varied; it affected to persons, production or commercial traffic. The author of this work makes an analysis for the two first ot these mechanism, studying the artisan of the city of Murcia, in teh XIV and XV centuries, the repercussions of thought taxes for the whole castilian crown circuit, and for the all feudal society too