Following the dynastic tradition the Habsburgs' hereditary territories were separated from this enormous empire at the Diet of Worms in 1521, when Charles I left them to the regency of his younger brother, Ferdinand I (1521–1564), although he then continued to add to the Habsburg territories. Since Charles left his Spanish Empire to his son Philip II of Spain, the Spanish territories became permanently alienated from the northern Habsburg domains, although remained allies for several centuries.
Following the dynastic tradition the Habsburgs' hereditary territories were separated from this enormous empire at the Diet of Worms in 1521 when Charles I left them to the regency of his younger brother Ferdinand I (1521–1564) although he then continued to add to the Habsburg territories Since Charles left his Spanish Empire to his son Philip II of Spain, the Spanish territories became permanently alienated from the northern Habsburg domains, although remained allies for several centuries.