State · 680 – 920
Kingdom of Seisyllwg
A state of 680 – 920 — 240 years in Europe. It followed Kingdom of Ceredigion. It was followed by Kingdom of Deheubarth. Its line of rulers holds 2 people.
For the full story, the article on Wikipedia (CC BY-SA 4.0); this page holds what the record says of the state.
- Stood
- 240 years
- 680 – 920
- Rulers
- 2
- the King of Seisyllwg
- Most ground
- 8,900 km²
- in 900
- Symbols
- 2
- on record, with years
Where it sits in time
Five thousand years, 3000 BCE to 2026; the state in gold, what it replaced or followed and what replaced or followed it in grey.
Before and after
The states the record files it as replacing or following, and those that replaced or followed it - Wikidata's own statements, each read from this state's side.
Before it
- Kingdom of Ceredigion · follows · 500 – 680
After it
- Kingdom of Deheubarth · followed by · 920 – 1197
Rulers
Read from the state’s own English article and its rulers’ articles, where Wikidata names no ruler.
| Ruler | Reign | Length | How it ended · source | To the ruler before |
|---|---|---|---|---|
| Cadell ap Rhodri | 872 – 909 | 37 years | ending not on record | |
| Hywel Dda | 909 – 920 | 11 years | ending not on record | child |
2 rulers, 2 with terms dated as terms, covering 872 – 920. Only 48 years of the line are dated - too short for a median. 0 of 1 handovers irregular - a killing, a deposition, a rival claimant, a rising or a coup beside it. A blank in the last column means no kin on record, which is coverage, never “unrelated”.
Ground held, by year
km² inside its borders as the borders dataset draws them, measured on an equal-area grid; a step series, held between the years the dataset maps.
4,600 km² in 880, 7,900 km² in 920; at its largest 8,900 km² in 900. Cliopatria, CC BY 4.0.
Flags and arms, in order
Each symbol with the years its own statement gives; the timeline flies the one of the year on screen.
coat of arms, undatedCoat of arms of Gwaethfoed, Prince of Ceredigion · CC BY-SA 3.0 · AlexD 
flag, undatedFlag of Ceredigion · CC BY-SA 3.0 · AlexD
Among all states
Each measure against the states that carry it, never against all of them: a bar is the share of those states below this one.
- How long it stood240 years
stood longer than 68% of 3,187 states with a recorded end or still standing.
- The most ground it held8,900 km²
held more ground at its peak than 14% of 1,465 states with a border in Cliopatria.
- Wars recorded per centurynone
had more wars on record per century than 44% of 3,187 states, counting the wars the atlas hosts under each.
- Rulers on record2
has more rulers on record than 34% of 1,968 states with a line of rulers.
What led to it, and what came of it
The investigation's own picture: 1 cause the record names and 1 result, the strongest six of each at their own years, joined to the state by the kind of claim - a recorded statement solid, the article's sentence dashed, a theory dash-dot.
Open the investigation: every row with its evidence, the conditions at the time, the theories condition by condition, and the succession analysed.
Open in the atlas
- On the timeline, 656 – 944, with everything that stood beside it.
- On the map in 900, live: scrub the year and watch its borders move.
- Investigate it: what led to it, what came of it, and its succession analysed.
Wikidata Q2456191 (CC0) · borders Cliopatria, CC BY 4.0 · coast and rivers Natural Earth · symbols from Wikimedia Commons, each credited above · data built 2026-10-06 · Pastlas v2.9.1, by Oleh Voronko. The published atlas and its data are for non-commercial use.