Commodus becomes sole emperor on Marcus Aurelius’s death, 17 March 180
On 17 March 180 Marcus died on the Danube and Commodus became sole emperor as received. In the causal graph this event weakens Democratic Resilience, a driver that strengthens Having a say in government — a worsening welfare path.
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On 17 March 180 Marcus died on the Danube and Commodus became sole emperor as received. This Fact is that succession instrument. Dio prints a decline-heading; that colour is attributed, not upgraded to a unique GDP series.
Context
A 19-year-old hereditary princeps after a philosopher-father is a democratic-resilience-adjacent shock in later senatorial memory. Offsets of early continuity sit on the peace row.
Commodus’s documented role is bounded by other offices and collaborators named in the sources below.
Dio’s famous gold-to-iron remark is a senatorial artist’s verdict, not a metal assay. Sole rule is a dated succession. Hereditary break with adoption is the political path. He did not typeset Loeb.
Why it matters
Confidence high on the date.
Who was responsible
Contribution type and responsibility level for each recorded actor — not sole-author shorthand.
Commodus
PersonDirect responsibility
responsibility level 0.4 · verified
What changed
Fact → Driver → Indicator. Relationship strength orders the paths; it is not the observed indicator movement.
- FactCommodus becomes sole emperor on Marcus Aurelius’s death, 17 March 180
- weakensDriverDemocratic Resilience
- strengthensIndicators (3)Having a say in government
impact weight 0.5 · Effect from 17 March 180 · verified
Confidence high on the date.
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 normalTwo readings: 30.2% of population aged 16-65 years (2021) and 29.8% of population aged 16-65 years (2023).
20212023 Above normal = 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 normal125 readings, 1900–2024: rose from 0.17 score from 0 to 1 to 0.53 score from 0 to 1.
Above normal = 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 normalAbove normal = better
Evidence
The sources behind this fact and its verification state.
- 1.Cassius Dio Book 73 (Loeb English) — CommodusLacusCurtius / University of Chicago · High credibility · verified
- 2.Britannica — CommodusEncyclopaedia Britannica · High credibility · verified
What the sources establish
Britannica and Loeb Dio independently date 17 March 180 as the sole-rule start.
Established: sole emperor from 17 March 180. Not established: Dio’s iron age as a measured series.
Commodus did not file a later UNESCO form, a later Loeb colophon, or a later museum label as a personal act. A deathbed succession is not a gladiator bout. Keep 180 distinct from 192.
Causal path
How this event connects to drivers and indicators in the graph.
- ActorCommodus
- contributed toFactCommodus becomes sole emperor on Marcus Aurelius’s death, 17 March 180
- weakensDriverDemocratic Resilience
- strengthensIndicatorHaving a say in government
Cite this page
Factrail. (2026). Commodus becomes sole emperor on Marcus Aurelius’s death, 17 March 180. Factrail. https://factrail.ai/facts/com-sole-rule-180
https://factrail.ai/facts/com-sole-rule-180
Accessed 16 October 2026.
By the Factrail desk · Method: how we source and score · Last reviewed
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