After Bladud had met his fate in this way, his son Leir was raised to the kingship. Leir ruled the country for sixty years. It was he who built the city on the River Soar which is called Kaerleir after him in the British tongue, its Saxon name being Leicester. [II.11]

LEICESTER appears in the Historia as King Leir's eponymous city, and is primarily associated with him: its second appearance comes in relation to his death:

Three years later Leir died; and Aganippus, King of the Franks, died too. As a result Leir's daughter Cordelia inherited the government of the kingdom of Britain. She buried her father in a certain underground chamber which she had ordered to be dug beneath the River Soar, some way downstream from Leicester. This underground chamber was dedicated to the two-faced Janus: and when the feast-day of the god came round, all the craftsmen in the town used to perform there the first act of labour in whatever enterprise they were planning to undertake during the coming year. [II.14]

Tatlock points out that there is confusion over the forms Caicestria and Legecestria, tending to agree with the argument that by the former we should understand CHESTER: Legecestria is one of many names which Chester has held, and Tatlock argues Geoffrey would have been keen to avoid confusion between the two places (pp. 24-25). While Tatlock assigns all the instances of Legecestria in the Historia to Leicester, I have here followed Lewis Thorpe in placing the massacre of the Bangor monks (in a place which, Tatlock notes, Bede called Legacaestir, p. 26) in CHESTER.

Leicester appears a few more times in passing in the Historia:

After a time, Archgallo fell into a coma; and when he died he was buried in the town of Leicester. [III.17]

Jugein of Leicester attends Arthur's plenary court [IX.12], and fights with him at the Battle of Saussy [X.6].