Later, the Prussian Grand Dukes gained control over the central German Electorate of Brandenburg creating the politically united but physically divided state of Brandenburg-Prussia. Brandenburg had had a weak feudal state structure, under which its ruler, the Elector, was subject to limitation by medieval parliamentary bodies known as Estates. In the seventeenth century however, the Junkers willingly surrendered the weakly established tradition of Estate limitations on the crown in return for guarantees by the crown of their unlimited control over their serfs and exemption from taxation. The lack of any significant bourgeoisie meant that there was no threat of a revolution on behalf of individual rights vis a vis monarchical absolutism from that sector. Thus the Junkers gained absolute control over agricultural labor, production and sales. They traded with western merchants who came to them, thus becoming entrepreneurs in a sense, while at the same time stifling the growth of any local bourgeoisie. The Junkers also dominated the bureaucracy and the army and formed a strong partnership with the absolutist monarchical state. In the nineteenth century, Prussia gradually began to modernize in the areas of mining and manufacture, but in contrast with England during the same period, the initiative came from the state with the Junker-dominated bureaucracy fulfilling the entrepreneurial role.