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 "stud", but this is not quite accurate; the Anglo-Saxon for "horse" is hors (genitive horses). His name Horsa (genitive Horsan) looks like a hypocoristic (pet-name) form for a compound word name whose first component is Hors-. Bede, the providing the earliest reference known to Horse, mentions a stone existed that recorded his name. Legend has it that Horsa was buried at Horsted, an area between Chatham in Kent and Bluebell Hill, on the road towards Maidstone.
Anglo-Saxon ChronicleReferencing the Battle of Aylesford, the Anglo-Saxon Chronicle entry for 455 states: Her Hengest ⁊ Horsa fuhton wiþ Wyrtgeorne þam cyninge, in þære stowe þe is gecueden Agælesþrep, ⁊ his broþur Horsan man ofslog; ⁊ æfter þam Hengest feng to rice ⁊ Æsc his sunu.
In modern English: 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.