Alexander (Byzantine emperor) in the context of "Constantine VII Porphyrogennetos"

The Byzantine–Bulgarian war of 913–927 (Bulgarian: Българо–византийска война от 913–927) was fought between the Bulgarian Empire and the Byzantine Empire for more than a decade. Although the war was provoked by the Byzantine emperor Alexander's decision to discontinue paying an annual tribute to Bulgaria, the military and ideological initiative was held by Simeon I of Bulgaria, who demanded to be recognized as Tsar and made it clear that he aimed to conquer not only Constantinople but the rest of the Byzantine Empire, as well.

In 917, the Bulgarian army dealt a crushing defeat to the Byzantines at the Battle of Achelous, resulting in Bulgaria's total military supremacy in the Balkans. The Bulgarians again defeated the Byzantines at Katasyrtai in 917, Pegae in 921 and Constantinople in 922. The Bulgarians also captured the important city of Adrianople in Thrace and seized the capital of the Theme of Hellas, Thebes, deep in southern Greece. Following the disaster at Achelous, Byzantine diplomacy incited the Principality of Serbia to attack Bulgaria from the west, but this assault was easily contained. In 924, the Serbs ambushed and defeated a small Bulgarian army on its way to Serbia, provoking a major retaliatory campaign that ended with Bulgaria's annexation of Serbia at the end of that year.

Constantine VII Porphyrogenitus (Medieval Greek: Κωνσταντῖνος Πορφυρογέννητος, romanized: Kōnstantīnos Porphyrogénnētos; 17 May 905 – 9 November 959) was the fourth Byzantine emperor of the Macedonian dynasty, reigning from 6 June 913 to 9 November 959. He was the son of Emperor Leo VI and his fourth wife, Zoe Karbonopsina, and the nephew of his predecessor Alexander.

Most of his reign was dominated by co-regents: from 913 until 919 he was under the regency of his mother, while from 920 until 945 he shared the throne with Romanos Lekapenos, whose daughter Helena he married, and his sons. Constantine VII is best known for the Geoponika (τά γεωπονικά), an important agronomic treatise compiled during his reign, and three, perhaps four, books; De Administrando Imperio (bearing in Greek the heading Πρὸς τὸν ἴδιον υἱὸν Ῥωμανόν), De Ceremoniis (Περὶ τῆς Βασιλείου Τάξεως), De Thematibus (Περὶ θεμάτων Άνατολῆς καὶ Δύσεως), and Vita Basilii (Βίος Βασιλείου), though his authorship of the Vita Basilii is not certain.

Eudokia (or Eudocia) Ingerina (Greek: Ευδοκία Ιγγερίνα, romanized: Evdokia Ingerina; c. 840 – c. 882) was a Byzantine empress as the wife of the Byzantine emperor Basil I, the mistress of his predecessor Michael III, and the mother of emperors Leo VI and Alexander, as well as the mother of Patriarch Stephen I of Constantinople.