Engelbert was the second son of Margrave
Engelbert II and his first wife Uta of
Passau. When his father succeeded his elder brother Henry as
Duke of Carinthia, Engelbert III received the margravial title in Istria. However, he mainly ruled in the Sponheim estates around
Kraiburg in
Bavaria, bequested by his mother. In 1135 Emperor
Lothair III dispatched him to a
synod at Pisa in
Italy, in order to back
Pope Innocent II against
Antipope Anacletus II. In turn, Engelbert was vested with the Imperial
March of Tuscany, but was succeeded by the
Welf duke
Henry X of Bavaria already in 1137. Engelbert attended the 1156
Imperial Diet in
Regensburg, where he witnessed the granting of the
Privilegium Minus by Emperor
Frederick Barbarossa, elevating the
March of Austria to a
duchy. In 1140 Engelbert had married
Matilda, youngest daughter of the Bavarian count
Berengar II of Sulzbach. He was thus a brother-in-law of
Gertrude of Sulzbach, consort of King
Conrad III of Germany, and
Bertha of Sulzbach, as
Irene wife of the Byzantine Emperor
Manuel I Komnenos. Matilda died late in 1165, the marriage remained childless. The margravial title in Istria passed to the Bavarian
Counts of Andechs. His son
Pellegrino was
Patriarch of Aquileia in northern Italy from 1195 to 1204. ==Notes==