Under the Hohenstaufen emperors (1138–1254), German princes encouraged German settlement to the south and east (). Members of the Hanseatic League, mostly north German towns, prospered in the expansion of trade. Population declined starting with the Great Famine in 1315, followed by the Black Death of 1348–50. The Golden Bull issued in 1356 provided the constitutional structure of the Empire and codified the election of the emperor by seven prince-electors.