Frederick (German: Friedrich) I (1371-1440), Burgrave of Nuremberg, was created margrave of Brandenburg by Sigismund, Holy Roman Emperor in 1415, inaugurating 400 years of rule over the area by the Hohenzollern family which was ultimately to preside over Germany's political unification.
Jobst paid very little attention to Brandenburg, and the period was used by many of the noble families to enrich themselves at the expense of the poorer and weaker towns, to plunder traders, and to carry on feuds with neighbouring princes.
Brandenburg was ravaged impartially by both parties, and in 1627 George William attacked his brother-in-law, Gustavus Adolphus of Sweden, who was using Prussia as a base of operations for his war against Poland.
Frederick's chief adviser about this time was Eberhard Danckelmann (1643-1722), whose services in continuing the reforming work of the great elector were very valuable; but having made many enemies, the electress Sophia among them, he fell from power in 1697, and was imprisoned for several years.
In 1320 the Brandenburg Ascanian line came to an end, and from 1323 until 1373 Brandenburg was under the control of the Wittelsbach family, better known as rulers of Bavaria.
Brandenburg was one of the German states to switch (1539) to Protestantism in the wake of the Reformation, and generally did quite well in the century following, as the dynasty expanded its lands to include the Duchy of Prussia (1618) and along the lower Rhine Cleves (1614) and elsewhere.
Brandenburg was still the most important portion of the kingdom (and the state was often referred to informally as Brandenburg-Prussia) but for the purposes of accuracy, the continuation of this history can be found at Prussia.