At this point, the Habsburg Empire was so vast that Charles V was constantly travelling throughout his dominions and therefore needed deputies and regents, such as Isabella of Portugal in Spain and Margaret of Austria in the Low Countries, to govern his various realms. At the Diet of Worms in 1521, Emperor Charles V came to terms with his younger brother Ferdinand. According to the Habsburg "compact" of Worms (1521), confirmed a year later in Brussels, Ferdinand was made Archduke, as a regent of Charles V in the Austrian hereditary lands.