|Roman imperial dynasties|
|Theodosius I as Emperor of the East||379–392|
|Theodosius I as sole emperor||392–395|
|-with Arcadius as junior Augustus of the East||383–395|
|Honorius as Emperor of the West||395–423|
|Arcadius as Emperor of the East||395–408|
|Theodosius II as Emperor of the East||408–450|
|Marcian as Emperor of the East||450–457|
The Theodosian dynasty was a Roman family that rose to eminence in the waning days of the Roman Empire.
Its founding father was Flavius Theodosius (often referred to as Count Theodosius), a great general who had saved Britannia from the Great Conspiracy. His son, Flavius Theodosius was made emperor of the Eastern Roman Empire in 379, and briefly reunited the Roman Empire 394–395 by defeating the usurper Eugenius. Theodosius I was succeeded by his sons Honorius in the West and Arcadius in the East. The House of Theodosius was related to the Valentinian Dynasty by marriage, since Theodosius I had married Galla, a daughter of Valentinian I. Their daughter was Galla Placidia. The last emperor in the West belonging to the dynasty was Galla Placidia's son Valentinian III. The last emperor of the dynasty in the East was Marcian, who became emperor by marrying Pulcheria, the older sister of Theodosius II, after the death of the latter. Later on Placidia, a daughter of Valentinian III, was married to Olybrius and Anthemius was a son-in-law of Marcian. Descendants of the dynasty continued to be part of the East Roman nobility at Constantinople until the end of the 6th century.
- Theodosius I (392–395)
- Arcadius (395–408)
- Honorius (395–423)
- Theodosius II (408–450)
- Valentinian III (425–455)
- Marcian (450–457)
- Count Theodosius and Thermantia
- Theodosius I
- From marriage between Theodosius I and Aelia Flaccilla.
- From marriage between Theodosius I and Galla. She was a daughter of Valentinian I and Justina.
- Galla Placidia. Married first Ataulf and secondly Constantius III.
- From marriage between Arcadius and Aelia Eudoxia.
- From marriage between Galla Placidia and Ataulf.
- From marriage between Galla Placidia and Constantius III.
- Valentinian III. Married his cousin Licinia Eudoxia.
- Justa Grata Honoria. Granted the title Augusta. Proposed marriage to Attila the Hun, treaty never concluded. Married Flavius Bassus Herculanus.
- From marriage between Theodosius II and Aelia Eudocia.
- The marriage of Pulcheria and Marcian was childless. However it brought into the dynasty a daughter of Marcian from a previous marriage.
- From marriage between Valentinian III and Licinia Eudoxia
- From marriage between Marcia Euphemia and Anthemius.
- From marriage of Eudocia and Huneric.
- From marriage of Placidia and Olybrius.
- From marriage of Anicia Juliana and Areobindus.
- From marriage of Olybrius and Irene.
- Proba. Married Anicius Probus Iunior.
- From marriage of Proba and Probus.
- Juliana. Married Anastasius.
- From marriage of Juliana and Anastasius.
- Honorius. Married Maria.
- From marriage of Honorius and Maria.