With his power over northern and central Italy secured, Otto I sought to clarify his relationship with the Byzantine Empire in the East. The Byzantine Emperor objected to Otto's use of the title "Emperor". The situation between East and West was finally resolved to share sovereignty over southern Italy. Otto I sought a marriage alliance between his Imperial house and the Eastern Macedonian dynasty. A prerequisite for the marriage alliance was the coronation of Otto II as Co-Emperor. Otto I then sent word for Otto II to join him in Italy. In October 967, father and son met in Verona and together marched through Ravenna to Rome. On December 25, 967, Otto II was crowned Co-Emperor by Pope John XIII, securing Otto II's succession to the Imperial crown following his father's death.