The Timeline of conflict in Anglo-Saxon Britain is concerned with the period of history from just before the departure of the Roman Army, in the 4th century, to just after the Norman Conquest in the 11th century.
The information is mainly derived from annals and the Venerable Bede. The dates, particularly from the fourth to the late sixth centuries, have very few contemporary sources and are largely later constructions by medieval chroniclers. The historian Diana Greenway described one such 12th-century chronicler, Henry of Huntingdon, as a 'weaver' compiler of history, and the archaeologist Martin Welch described the Anglo-Saxon Chronicle as "a product of the West Saxon court... concerned with glorifying the royal ancestry of Alfred the Great. Manipulation of royal genealogies, in this and other sources, to enhance the claims of contemporary rulers was common. Literary formulas associated with original myths are a common feature of earlier entries." Although the timeline uses the annals for this period of history, information provided by these sources can be problematic, particularly with the earlier dates.
Chronology
Constructing a chronology of the early Anglo-Saxon period, and how the Anglo-Saxons took over land in Britain from Romano-Britons (Celtic-speakers, Latin-speakers, or both), is highly complex. The limitations of source material place constraints on just how accurate any chronology can be. As an example, the following table shows how much variation there is between historians on just one date, the Battle of Badon:
Much of the dating of the period comes from Bede (672/673–735), who in his Ecclesiastical History of the English People, tried to compute dates for events in early Anglo-Saxon history. Although primarily writing about church history, Bede is seen as Britain's first true historian, in that he cited his references and listed events according to dates rather than regnal lists. So we know that he relied heavily on De Excidio et Conquestu Britanniae by Gildas, a sixth-century cleric, for his early dates and historians have found Gildas unreliable where dates were concerned. Bede's work was widely read among the literate in the Anglo-Saxon kingdoms, and his dates were used by the monks who compiled the various Anglo-Saxon Chronicles from the late ninth century onwards. Some sources say that the Saxon warriors were invited to come, to the area now known as England, to help keep out invaders from Scotland and Ireland. Another reason for coming may have been because their land often flooded and it was difficult to grow crops, so they were looking for new places to settle down and farm.
The most controversial dates in the period—those from the fourth to the late sixth centuries—have very few contemporary sources, and are mainly derived from later attempts to construct Anglo-Saxon history.
The following is an outline of some events recorded in Bede's Ecclesiastical History, the Anglo-Saxon Chronicle, the Welsh Annals (Annales Cambriae), and Brut y Tywysogion. Many of the dates from the fourth, fifth, and sixth century are points of contention.
AC = "from the Annales Cambriae" (English translation at this link). ASC = "from the Anglo-Saxon Chronicle". B = "from Bede's writings". ByT = "from Brut y Tywysogion". (?) = Dates and events that are contentious or subject to debate.
4th century
360 and after, and perhaps before: various Germanic peoples (Alemanni, Saxons, etc.) came to Roman Britain: raiders, Roman armies recruited from among German tribes, some settlers (The Saxon Shore ()).