Horsa, according to tradition, was a fifth century warrior and brother of Hengest who took part in the invasion and conquest of Britain from its native Romano-British and Celtic inhabitants. It is often said that his name is Anglo-Saxon for "horse", but this is not quite accurate; the Anglo-Saxon for "horse" is hors (genitive horses). His name Horsa (genitive Horsan) looks like a hypocoristic form for a compound word name whose first component is Hors-.
The Anglo-Saxon Chronicle entry for 455 says that "Her Hengest 7 Horsa fuhton wiþ Wyrtgeorne þam cyninge, in þære stowe þe is gecueden Agælesþrep, 7 his broþur Horsan man ofslog; 7 æfter þam Hengest feng to rice 7 Æsc his sunu." (Here Hengest and Horsa fought against King Vortigern in the place that is called Aylesford, and his brother Horsa was killed, and after that Hengest and his son Æsc took the kingdom.) (See Battle of Aylesford (in Kent)).
It is said that a monument was raised in his memory (White Horse Stone near Maidstone is the traditional site); but see the next paragraph.
Twin warriors are a common theme in folklore, and because our earliest witness to Horsa's existence, Bede, mentions a stone existed that recorded his name, recent scholars have speculated that perhaps:-
Anglo-Saxon peopleMercenaries | Arthurian legend | English heroic legends | Sub-Roman Britain | Horsa | Horsa | Horsa av Kent | Horsa7