- Mercia, covering central England
- Northumbria, covering northern England
- Wessex, covering south-west England
- East Anglia, covering eastern England
- Kent, covering part of south-east England
- Sussex, covering another part of south-east England
- Essex, covering another part of south-east England
The last three were much smaller than the others and survive today as counties, but the others are much larger and cover many counties. There were also other small kingdoms that were absorbed by the larger ones.
The history of this period is one of almost constant conflict between the seven kingdoms, with each of them vying for dominance over the others. All of them except Essex experienced periods of dominance, but the most successful was Mercia, which was dominant from the mid 7th to the mid 9th centuries AD.
It was also a period that began with the English still a pagan race, and saw the gradual introduction of Christianity to the various kingdoms at different times. By the end of the period the English were all officially Christian, though paganism survived in remote areas for centuries afterwards. The first Archbishop of Canterbury was a Roman Catholic monk named Augustine who arrived in England in 597 AD.
The period of the Heptarchy begins with the collapse of central authority in England after the legendary time of King Arthur in the 6th century when Britons and Anglo-Saxons were fighting for possession of the land and also against invaders from Ireland and Scotland. It ends in the 9th century when the country faced another wave of invaders, the Vikings, who were still pagans. In the face of this new threat the English put aside their differences and united under King Alfred the Great of Wessex, the first true historical king of England.