A small piece of pottery discovered during an archaeological dig has provided a glimpse into Dereham's medieval past.

The excavation, or trial by trenching, of the former library site in Church Street is being headed by Chris Birks Archaeological Services, based in Frettenham, near Norwich.

It was originally ordered by Breckland Council and Norfolk County Council's Historic Environment Service, based at the Gressenhall Farm and Workhouse Museum, near Dereham.

An application has been approved by the council to build flats on the previously unexplored site and it is part of the planning process to carry out an archaeological survey.

In early 2010 the library was demolished and the planning proposal was submitted by Acorn Building Services Norfolk.

The excavation, which started two weeks ago, is due to finish next week and on January 12 a small piece of pottery was found which is believed to date back to the 14th century.

Mr Birks said: 'It is a great opportunity to try to understand what happened in the middle of Dereham in the past. It is confirming the settlement activities from the medieval period.

'Although it is only one piece of pottery, it is about getting an understanding of what people's lives were like at the time.

'As a find it is not rare, but it is important to find out that settlement took place. This is a significant opportunity to understand the history of this part of the town.'

The pottery, which was found in one of four trenches, has remnants of soot on it and is believed to have been part of a cooking pot. Other items found in the four trenches included general domestic waste.

Mr Birks said that settlement during the medieval period spread from church buildings and the former library site is on a historical street between St Nicholas' Church and the Market Place.

Much of the archaeology of the town was thought to have been lost in a series of fires between 1581 and 1659.

Only two of the town's original buildings survived, the church and Bishop Bonner's 16th century cottage.

Another discovery from the four trenches was a waste pit at the back of the site which would have served houses.

A set of steps, possibly leading to a cellar, was also found which indicated the homes were built in the 19th century, according to Mr Birks.

He added that a lot of evidence would have been removed during the 1960s when the library was built.

After the dig is finished the trenches will be filled in and the piece of pottery will be archived by the Norfolk Museums Service. The church has Norman origins and, it has been claimed, lies on the site of an earlier Middle Saxon nunnery.

Dereham is thought to have emerged from a settlement pre-dating the Saxon era and named after a deer park that existed in the area.