Theophanes (Greek: Θεοφάνης, fl. ca. 925–945) was a Byzantine palace official and the chief adviser of Emperor Romanos Lekapenos (r. 920–944) during most of his reign. He was also an active and able diplomat, and led the naval defense of Constantinople against the Rus' invasion of 941.
Nothing is known of Theophanes's origin and early life. He first appears in the sources in October 925, as imperial protovestiarios, when he became the closest adviser (paradynasteuon) of Emperor Romanos I Lekapenos upon the downfall of his earlier chief aide, John Mystikos. Unlike Mystikos, Theophanes would prove both capable and loyal to his master, and remained the chief figure of the government for the remainder of Romanos's reign.
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.