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eventVerified

Gratian proclaims Theodosius eastern co-emperor on 19 January 379 after Adrianople

Valens died at Adrianople on 9 August 378. In the causal graph this event strengthens Democratic Resilience, a driver that strengthens Having a say in government — an improving welfare path.

Sources: [1][2]

Read the full account

Context

Restoring an eastern command after a field army’s destruction is a resilience heading.

Theodosius I’s documented role is bounded by other offices and collaborators named in the sources below.

Valens died at Adrianople on 9 August 378. Britannica: Gratian summoned Theodosius and proclaimed him co-emperor on 19 January 379 over the East including Dacia and Macedonia. The 438 code is not this act. Shared tetrarchic-style colleague rule remains.

Who was responsible

Contribution type and responsibility level for each recorded actor — not sole-author shorthand.

  • Theodosius I

    Person

    Direct responsibility

    responsibility level 0.4 · verified

What changed

Fact → Driver → Indicator. Relationship strength orders the paths; it is not the observed indicator movement.

    1. FactGratian proclaims Theodosius eastern co-emperor on 19 January 379 after Adrianople
    2. strengthensDriverDemocratic Resilience
    3. strengthensIndicators (3)Having a say in government
    Improving path

    impact weight 0.5 · Effect from 19 January 379 · verified

    • Having a say in government

      via Democratic Resilience

      Better

      Strengthens · Relationship strength 0.35 (weight 0.5 × strength 0.7)

      Observed

      29.8% of population aged 16-65 years · 8.13 below the normal line (2023)

      Worse than normal

      Two readings: 30.2% of population aged 16-65 years (2021) and 29.8% of population aged 16-65 years (2023).

      20212023

      Above normal = better

    • Clean elections index

      via Democratic Resilience

      Better

      Strengthens · Relationship strength 0.23 (weight 0.5 × strength 0.45)

      Observed

      0.53 score from 0 to 1 · 0.34 below the normal line (2024)

      Worse than normal

      125 readings, 1900–2024: rose from 0.17 score from 0 to 1 to 0.53 score from 0 to 1.

      Above normal = better

    • WJP Rule of Law Index (global)

      via Democratic Resilience

      Better

      Strengthens · Relationship strength 0.23 (weight 0.5 × strength 0.45)

      Observed

      0.55 index score (0-1) · 0.26 below the normal line (2024)

      Worse than normal

      Above normal = better

Evidence

The sources behind this fact and its verification state.

Verified2 sources on file
  1. 1.De Imperatoribus Romanis — Theodosius ILoyola University Chicago · High credibility · verified
  2. 2.Britannica — Theodosius IEncyclopaedia Britannica · High credibility · verified
What the sources establish

Britannica records the 19 January 379 proclamation after Theodosius had again proved himself against the Sarmatians. DIR independently narrates Gratian’s appointment.

Theodosius I did not file a later UNESCO form, a later Loeb colophon, or a later museum label as a personal act.

Causal path

How this event connects to drivers and indicators in the graph.

  1. ActorTheodosius I
  2. contributed toFactGratian proclaims Theodosius eastern co-emperor on 19 January 379 after Adrianople
  3. strengthensDriverDemocratic Resilience
  4. strengthensIndicatorHaving a say in government

Cite this page

Factrail. (2026). Gratian proclaims Theodosius eastern co-emperor on 19 January 379 after Adrianople. Factrail. https://factrail.ai/facts/theo-appointment-379

https://factrail.ai/facts/theo-appointment-379

Accessed 16 October 2026.

By the Factrail desk · Method: how we source and score · Last reviewed

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