In the county of Flanders, the later Middle Ages should not be considered simply as a period of general crisis for the nobility as an evolving class. Instead, we might call it a time of intensive renewal, accelerated mobility and diversification. The background of these developments was a threefold dialectic: the late mediaeval crisis of feudalism (which brought about a sharp deterioration of noble rent income), social and economic urban development in Flanders and, last but not least, the Flemish-Burgundian state formation process. Specifically, the latter factor has been taken into account in this article as a creative force in the renovation of the nobility. This process was accompanied by a concentration of surplus extraction on the 'state' level, resulting in what we might call ‘state feudalism’. For the traditional nobles, obtaining a political position in the county was now only possible through princely service. On the other hand, political functions and offices offered urban and rural, non-noble, political elites opportunities for gradual ennoblement. Of course, other factors too were involved: the acquisition of seigniorial power, noble alliances and ‘living like a nobleman’. Consequently, these two aristocracies (traditional nobles and political elites of the Burgundian State) merged to a certain extent, eventually resulting in a 'new' noble class, anticipating the ‘noblesse de robe’ of the modern period. For a particular family, this process of ennoblement could take several generations. In a European perspective, the redefinition and revitalisation of this ‘nobility’ as a traditional ruling class in feudal society is hardly surprising. Nevertheless, the high degree of urbanisation in Flanders gave this process a distinct character.