Calleva Atrebatum is the original name of what we now know as the "Silchester Roman town" and is about 1 mile (1.6 km) east of Silchester. It was founded/built by the Atrebates tribe in the iron age (at about 100 BC), and then became a town in the Roman provice of Roman Britain (Brittania) in 43 AD.

The town was deserted at the 5th to 7th century, which is unusually late for Roman settlements which have not survived till now, and are in parts larger cities.

A suggestion as to why it was deserted after the Romans left is that they had already established settlements at Winchester and Dorchester. After about 100 years the twin Saxon towns were founded: Basing and Reading, which did not help Calleva Atrebatum survive and contributed to it getting abandoned.

The ruined walls are still there, and there is a footpath along them. An amphitheatre (outside the city walls on the east side) which was added AD 70-80 is also clearly visible outside of the city walls. A bit south of the ampitheatre is a small medieval church. The emerging spring on site was used for nearby baths. Inside, the land is used by farmers.

There were some excavations about the beginning of last century (1890 - 1909) which it is believed destroyed evidence, which might not have happened with the current technology available.

Since the 1970 the University of Reading became more involved in excavations and interesting finds could be made also as far as the Iron Age.

I have posted some ideas and links to the sources which could be of interest.

The Site is owned by Hampshire County Council, managed by English Heritage and is open to public during daylight hours. The public footpath around the walls and access to the theatre is free of charge.

Ideas:
I have been here a couple of times and it is a nice walk - can get a little muddy in places when its raining a lot, which happened to me. The excavations are only for about 6 weeks in summer but are worth while visiting. These excavations are partly open to the public - it is worth while checking on the below website, or if you are already there you could probably ask. These are the only excavations I have seen "real time" and not on TV, a great experience.

Logging of the Cache:
At N 51° 21.506'W 01° 05.220' you will find a information board. The Password to log the Cache is the first and last word of the Title. (both as they stand on the board and without spaces).

It would be also great if you could post a photo of you, or GPS at the Roman town.

Some interesting links:

English Heritage
http://www.english-heritage.org.uk/daysout/properties/silchester-roman-city-walls-and-amphitheatre/directions

Calleva Atrebatum
http://en.wikipedia.org/wiki/Calleva_Atrebatum

Univerity of Reading (more information about excavations)
http://www.reading.ac.uk/silchester/visit-the-roman-town/sil-visit-silchester-roman-town.aspx#park