John Angelus of Syrmia

John Angelus
Governor of Syrmia
Reign	1235–1254
Predecessor	new creation
Successor	Rostislav Mikhailovich (?)
Noble family	Angelos
Father	Isaac II Angelos
Mother	Margaret of Hungary
Born	c. 1193
Died	1259

John Angelus or Johannes Angelos (Greek: Ἰωάννης Ἄγγελος, Hungarian: Angelos János; c. 1193 – 1259), also known as Good John (Kaloiōannēs), was a Byzantine prince who migrated to Hungary and ruled the Duchy of Syrmia (Sirmium, Szerém) and its surroundings from 1235 until 1254, as a vassal under king Béla IV of Hungary, his maternal relative.

John Angelus was the son of Isaac II Angelos, the Byzantine Emperor from 1185 to 1195, and again from 1203 to 1204; and Margaret of Hungary, the daughter of King Béla III (r. 1172–1196) and sister of King Emeric (r. 1196–1204). John had three older siblings from his father's first marriage: Euphrosyne Angelina, Irene Angelina and Alexios IV Angelos, while he had a younger full brother, Manuel Angelos (b. after 1195 – d. 1212).

The family found refuge in the Hungarian court in 1222.

Andrew II of Hungary (r. 1205–1235), his uncle, gave him "Syrmia and beyond", i.e. south of the Sava river, including Belgrade, and the districts of Barancs and Macsó, which he ruled until 1254.

Béla IV appointed John Angelus as the governor of Syrmia, and Rostislav Mikhailovich as the governor of Slavonia, securing his southern boundaries while heading towards the Adriatic. Another source claims that he ruled Syrmia and Bačka from ca. 1230.

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