Astolat is a legendary city of Great Britain which is named in Arthurian legends. It is named as the home of Elaine of Astolat "the fair maiden of Astolat" and of her father Sir Bernard of Astolat. King Arthur is an important figure in the mythology of Great Britain, where he appears as the ideal of kingship in both war and peace. ... A figure in Arthurian legend, Elaine was the figure of unrequited love later solemnized in Alfred Tennysons poem The Lady of Shalott Also referred to varyingly as Elaine the White and Elaine the Fair, she is the daughter of Bernard of Astolat. ...

In chapter nine of Sir Thomas Malory's book Le Morte d'Arthur he cites Guildford in Surrey as the location of the legendary Astolat.
Sir Thomas Malory (c. ... Guildford is the county town of Surrey, England, as well as the seat for the borough of Guildford and the administrative headquarters of the South East England region. ... Surrey is a county in southern England, part of the South East England region and one of the Home Counties. ...

And so upon the morn early Sir Launcelot heard mass and brake his fast, and so took his leave of the queen and departed. And then he rode so much until he came to Astolat, that is Guildford; and there it happed him in the eventide he came to an old baron’s place..

Malory contrived his book from various early medieval sources about the life of Arthur. There is much speculation about all elements of these tales and their relation to historical truth, but in most cases there is evidence to suggest that the stories were based on real events and places during the period in Britain known as the dark ages. There is speculation that there could be a connection between the name Astolat and the Atrebates tribe who existed in this area before, and to a lesser degree after, the Roman occupation of Britain. In this case Astolat could refer to a realm, not necessarily a city. If did refer to a city some historians assert it would then more likely be a reference to Calleva Atrebatum the civitas of the Atrebates tribe which is known to have resisted the Anglo-Saxon advance in south eastern Britain for long after the rest of the area had yielded. In other sources Astolat is said to be located midway between London and Colchester which would place it near Chelmsford in Essex. Petrarch, who conceived the idea of a European Dark Age. From Cycle of Famous Men and Women, Andrea di Bartolo di Bargillac, c. ... The Atrebates (meaning settlers) were a Belgic tribe of Gaul and Britain before the Roman conquests. ... Roman or Romans has several meanings, primarily related to the Roman citizens, but also applicable to typography, math, and several geographic locations. ... The walls and church Inside the walls; note far walls in distance Silchester Roman Town, or Calleva Atrebatum, was an Iron Age and subsequently Roman town and capital of the Celtic tribe named the Atrebates, located near the modern village of Silchester on what is today the border between the... The Anglo-Saxons refers collectively to the groups of Germanic tribes who achieved dominance in southern Britain from the mid-5th century, forming the basis for the modern English nation. ... London is the capital city of the United Kingdom and of England. ... Colchester is a town and main settlement of the Colchester borough of Essex in the East of England. ... Chelmsford is a town in the county of Essex, in the United Kingdom. ... Essex is a county in the East of England. ...

References

http://www.arthurian-legend.com/le-morte-darthur/le-morte-darthur-18c.php

City of the Dead: the Roman Town of Calleva Atrebatum By Professor Michael Fulford