At that time, the Byzantine Empire had been embroiled in a protracted and disastrous war with Bulgarian Tsar Simeon (r. 893–927). In 927, however, Simeon died, and his infant son, Peter, ascended the Bulgarian throne under the regency of his uncle George Sursubul. Despite its victories, Bulgaria was exhausted from decades of warfare, and was furthermore threatened in its northern borders by the Magyars. Consequently, the Bulgarians decided to make peace with Constantinople. Negotiations followed at Mesembria, which proved successful: not only was peace agreed upon, but the links between Byzantium and Bulgaria were to be strengthened by a dynastic marriage of Tsar Peter with Maria Lekapene, the Byzantine emperor's granddaughter. Theophanes played a crucial role in the negotiations prior to the final signing of the treaty, and, together with Sursubul, was witness at the wedding of Peter and Maria. Theophanes proved his diplomatic skills yet again in April 934, when a large Magyar raid descended into Thrace. He met the raiders in person and arranged terms for their withdrawal and for the release of their captives in exchange for sums of money.