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 25 December 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. Otto II's coronation allowed marriage negotiations to begin with the East. Only in 972, six years later, under the new Byzantine Emperor John I Tzimiskes, was a marriage and peace agreement concluded, however. Though Otto I preferred Byzantine Princess Anna Porphyrogenita, daughter of former Byzantine Emperor Romanos II, as she was born in the purple, her age (then only five years old) prevented serious consideration by the East. The choice of Emperor John I Tzimisces was his niece Theophanu, who was the soldier-emperor's niece by marriage. On 14 April 972, the sixteen-year-old Otto II was married to the fourteen-year-old Eastern princess, and Theophanu was crowned empress by the Pope. Even after his coronation, Otto II remained in the shadow of his overbearing father. Though the nominal co-ruler of the Empire, he was denied any role in its administration. Unlike his earlier son Liudolf, whom Otto I named Duke of Swabia in 950, Otto II was granted no area of responsibility. Otto II was confined primarily to northern Italy during his father's time south of the Alps. After five years away, the Imperial family returned to Saxony in August 972. On 7 May 973, Otto died of fever, and Otto II succeeded his father as sole Emperor without meeting any opposition. Otto II spent his reign continuing his father's policy of strengthening Imperial rule in Germany and extending it deeper into Italy. Reign as emperor Coronation and domestic strife When Otto the Great died, the smooth succession to the imperial throne of Otto II had long been guaranteed. Otto II had been king of Germany for twelve years and Emperor for five at the time of Otto the Great's death. Unlike his father, Otto II did not have any brothers to contest his claims to the throne. On May 8, the nobles of the Empire assembled before Otto II and, according to the Saxon Chronicler Widukind of Corvey, "elected" Otto II as his father's successor. One of Otto II's first acts was to confirm the rights and possessions of the Archbishop of Magdeburg.