The House of Habsburg (; ), or House of Austria, was one of the most important royal houses of Europe. The throne of the Holy Roman Empire was continuously occupied by the Habsburgs between 1438 and 1740. The house also produced emperors and kings of the Kingdom of Bohemia, Kingdom of England (Jure uxoris King), Kingdom of France (Queen consort), Kingdom of Germany, Kingdom of Hungary, Empire of Russia, Kingdom of Croatia, Second Mexican Empire, Kingdom of Ireland (Jure uxoris King), Kingdom of Portugal, and Habsburg Spain, as well as rulers of several Dutch and Italian principalities. From the sixteenth century, following the reign of Charles V, the dynasty was split between Austrian and Spanish branches. Although they ruled distinct territories, they nevertheless maintained close relations and frequently intermarried.