Under the preceding Romano-British administration the area of Kent faced repeated attacks from seafaring raiders during the fourth century AD.

Following the end of Roman administration in 410, further linguistically Germanic tribal groups moved into the area, as testified by both archaeological evidence and Late Anglo-Saxon textual sources.

[2] As the closest part of Britain to mainland Europe, it is likely that Kent would have experienced many attacks from seafaring raiders, resulting in the construction of four Saxon Shore Forts along the Kentish coast: Regulbium, Rutupiae, Dubris, and Portus Lemanis.

[2] It is also likely that Germanic-speaking mercenaries from northern Gaul, known as foederati, would have been hired to supplement official Roman troops during this period, with land in Kent as payment.

[4] There is evidence that over the fourth and early fifth centuries, rural villas were abandoned, suggesting that the Romano-British elite were moving to the comparative safety of fortified urban centres.

[2] In 410, the Roman Emperor Honorius sent a letter to his British subjects announcing that they must thenceforth look after their own defence and could no longer rely on the imperial military to protect them.

[7] According to archaeologist Martin Welch, the fifth century witnessed "a radical transformation of what became Kent, politically, socially and in terms of physical landscape".

[1] There has been much debate as to the scale of Jutish migration; some see it as a mass migration in which large numbers of Germanic peoples left northern Europe to settle in Britain, pushing the native British population to western Britain or Brittany; others have argued that only a small warrior elite came over, dominating (or even enslaving) the Romano-British population, who then began using the Old English language and material culture of the newcomers.

[7] According to the Anglo-Saxon Chronicle, a "king of the Britons" known as Vortigern invited two Germanic leaders, Hengist and Horsa ("stallion" and "horse"), to Britain to help defend against Pictish raiders.

After arriving at Ypwinesfleot (Ebba's Creek, modern Ebbsfleet near Ramsgate) in Kent in 449, Hengist and Horsa led the defeat of the Picts before turning on the British and inviting more Germanic tribes to colonise Britain.

[15] Scholars often view Hengist and Horsa as mythological figures borrowed from folk tradition, to legitimise rulers in the Mid-to-Late Anglo-Saxon period.

[22] Little archaeological evidence of these early settlements exists, but one prominent example is a grubenhaus at Lower Warbank, Keston that was built atop the site of a former Roman villa, adjacent to a Romano-British trackway through the North Downs.

[28] Sixth century Kentish artefacts have been found in continental Europe, in particular in the areas of modern Charente, western Normandy, the Rhineland, Frisia, Thuringia, and southern Scandinavia.

They are relatively absent between the Sein and the Somme across the English Channel from the Saxons in Sussex, suggesting that trade was established between particular tribal or ethnic groups rather than by geography.

[29] There is also archaeological evidence of Kentish trade links in Hampshire and the Isle of Wight, and copies or imitations appearing in cemeteries further afield, in areas such as Wiltshire and Cambridgeshire.

[31] The monk Bede refers to Kent as ruled by Æthelberht at this period, making him the earliest reliably attested Anglo-Saxon monarch.

[35] According to Bede, the Christianization of Anglo-Saxon England began in Kent under Æthelberht's reign when the Benedictine monk Augustine arrived on the Ebbsfleet peninsula in 597, bringing the Gregorian mission with him.

[37] Various seventh and eighth century documents attest to the fact that Kent was governed by two kings, possibly a dominant one in the east and a subordinate in the west, perhaps reflecting the earlier divide.

[38] Trade with Francia was extensive in the seventh and eighth centuries and appears to have been under control of the kings of Kent, through the ports of Dover, Sarre and Fordwich.

[39] This period witnessed the end of furnished burial, marked archaeologically by less regional distinctiveness of grave goods and more artefacts decorated in the Salin Style II motifs.

A battle was fought at Otford in 776, and although the outcome is unknown, records of following years suggest that the rebels prevailed; Egbert II and later Ealhmund seem to have ruled independently of Offa for nearly a decade thereafter.

[48] In the late seventh century, the earliest charters appear, giving estate boundaries,[49] and showing reclamation of land, for use by livestock, from the Wantsum Channel and Romney Marsh.

[50] Canterbury grew into the economic and political centre of Kent during the seventh century, as evidenced by rubbish pits, metalworking, timber halls, and sunken-feature buildings from the period.

Rather than just acting as overlord of his new possession, he attempted to annex it or at least reduce its importance by creating a new diocese in Mercia at Lichfield, possibly because the archbishop of Canterbury Jænberht refused to crown his son Ecgfrith.

[56] In 804, the nuns of Lyminge were granted refuge in Canterbury to escape the attackers, while in 811 Kentish forces gathered to repel a Viking army based on the Isle of Sheppey.

Between 5000 and 10,000 men, with their families and horses, came up Limen estuary (the east-west route of the Royal Military Canal in reclaimed Romney Marsh) and attacked a Saxon fort near St Rumwold's church, Bonnington, killing all inside.