By the year 1000, Italy was divided between a number of different empires, kingdoms and regional leaders In 961 Otto I of Germany had invaded the Kingdom of the Lombards, uniting the crowns of Italy and Germany, and creating the Holy Roman Empire. Lombardy was the nucleus of imperial Italy, along with the ‘marches’ of Tuscany and Verona. Otto III was declared Holy Roman Emperor in 996, making Rome his administrative capital. Also in Rome was the seat of power of the pope, who held supranational sway across many of the Christian states in the area. In the south, the Byzantine Empire held territory under the Catepanate of Italy, along with a number of small port cities with which Constantinople maintained close ties. The power structure in the Italian islands was less well defined as the nominally Arab lands were subjected to frequent Byzantine revolts.