Demetrios Laskaris Leontares

Demetrios Laskaris Leontares or Leontarios (Greek: Δημήτριος Λάσκαρις Λεοντάρης, died 6 September 1431) was an important Byzantine statesman and military leader of the early 15th century, serving under the emperors Manuel II Palaiologos (r. 1391–1425) and John VIII Palaiologos (r. 1425–1448).

Nothing is known of Leontares's early life, except a statement by the historian Doukas that Leontares had served with distinction as an officer in the Morea and Thessaly in the 1390s. Leontares first appears in the historical sources in 1403. As a close friend and trusted agent of Manuel II, he escorted John VII Palaiologos to Thessalonica, the Byzantine Empire's second city, which John VII had been granted as a semi-independent appanage by Manuel. Leontares remained in the city and served as John VII's advisor and liaison to Manuel II until the former's death in 1408. At this point, Manuel placed him as tutor and regent over his young son, the despotes Andronikos Palaiologos, who succeeded John VII as governor of Thessalonica.

Leontares remained in Thessalonica as its effective governor until 1415/16, when the Ottoman prince Düzmece Mustafa and Junayd of Aydın fled to the city after a failed attempt to seize the Ottomans' European domains from Mehmed I (r. 1413–1421). Mehmed demanded the surrender of the rebel, but Leontares referred him to Manuel II in Constantinople. Eventually, a deal was reached whereby Mustafa would be kept in exile in the Byzantine island of Lemnos and Junayd in Constantinople, in exchange for an annual subsidy of 300,000 aspers. Leontares himself escorted Mustafa on the ship to Constantinople.

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