Ivanko (Bulgarian: Иванко, Greek: Ιβαγκός), also referred to by some scholars as Ivanko-Alexius,^[1][2] was a Vlach^[3] boyar who killed his cousin Ivan Asen I, the ruler of the renascent Second Bulgarian Empire, in 1196.^[4][5] He was a leader of local Vlachs and Bulgarian Slavs.

It is not known when and where Ivanko was born.^[6] Ivanko served in Bulgarian ruler and his cousin Ivan Asen's court.^[4][7] In 1196, Ivanko murdered Asen.^[8][9][10] The murder occurred when Asen angrily summoned Ivanko to discipline him for having an affair with his wife's sister.^[11] Bulgarian historian Vasil Zlatarski attributed this murder by Ivanko to the Cuman faction in Bulgarian court, as opposed to other explanations involving anti-Vlach Bulgarian boyars, boyar discontent with his harsh rule, Byzantine intrigue, etc.^[12] After the murder, he seized the Bulgarian capital Tarnovo and requested the assistance of the Byzantines. However, the Byzantine army mutinied on its way and thus let Asen's brother Peter claim the throne, forcing Ivanko to flee to Byzantine capital Constantinople.^[13][14][15]

In 1197, Ivanko married Theodora Angelina, the daughter of Anna Angelina and the sebastokrator Isaac Komnenos.^[10][16] Theodora's father had died in Bulgarian captivity not many months earlier.^[17] After the marriage, Ivanko adopted the Greek name Alexius.^[1] His grandfather-in-law, Byzantine emperor Alexios III Angelos, gave the command of Philippopolis to him to deal with Bulgarian raids.^[13][18] Ivanko recruited and trained an army of his fellow Vlachs to deal with the raiders, but ended up rebelling against the Byzantines.^[13][19] In this period, he had set up an independent principality in Rhodope and central Thrace.^[20] He captured the Byzantine general Manuel Kamytzes, who was sent against him;^[13] Kamytzes was ransomed by his son-in-law, Ivanko's rival, Dobromir Chrysos.^[21]

The emperor's sons-in-law Alexios Palaiologos and Theodore Laskaris marched against Ivanko in 1200.^[2] Ivanko was eventually captured when Alexios invited him to a peace council but imprisoned him instead.^[22] He was executed by his order.^[16] After his death, his fortresses were recovered by the Byzantines.^[22][23]

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