Norwich is one of the oldest cities in the country and has links to the Romans, Normans, Anglo-Saxons - and even Vikings.

Although long since mostly demolished, traces of the city's once mighty walls can still be seen today. 

Here we take a look at the history of the last two remaining towers that formed part of Norwich's impressive defences - Cow Tower and Black Tower. 

Eastern Daily Press: Today Black Tower stands alone on the Bracondale HillToday Black Tower stands alone on the Bracondale Hill (Image: Newsquest)

The building of the city walls commenced in 1294 and finished during the first half of the 14th century.

After construction, the city contained around a square mile of land which at the time made it larger than the City of London.

But despite the wall's size - reaching seven metres high and seven feet thick in certain places - they were unable to repel invaders during Litester's Rising in 1381 and Kett's Rebellion in 1549. 

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They were, however, extremely important in preventing the spread of infection during the great plagues of the 1600s.

Black Tower, also known as the Snuff Tower or the Duke of Buckingham's Tower, located in Bracondale, was one of the largest towers along the wall, reaching 11 metres high on its inner side and spanning a width of 10 meters.

Its name is thought to have come from the relatively small amount of mortar applied between the stones which would have allowed the flint faces to shine black. 

Eastern Daily Press: The tower stands completely gutted but once would have had a number of timber floors The tower stands completely gutted but once would have had a number of timber floors (Image: Newsquest)

Although designed to deter potential attackers, Black Tower was mostly used as part of the wall and gate that would stop boats from entering the city and collect tolls at Carrow Bridge. 

The tower would have been an imposing sight for those approaching the city and boats were heavily taxed and paid a fee in proportion to the amount of goods they carried. 

Those that were allowed to pass could carry on upriver toward Cow Tower. 

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Built in 1398 and named after the surrounding area, Cowholme, it was the largest tower in Norwich and was used to house recently developed cannons to defend the city from river attacks - one of the first of its kind in the country. 

The walls of the tower were built with a core of mortared flint rubble and it had three floors including the ground floor which may have been a communal dining room when occupied. 

A total of 36,850 bricks were ordered for the tower's construction and at least 170 cartloads of stone.

Eastern Daily Press: Cow Tower during the 1912 floodsCow Tower during the 1912 floods (Image: Newsquest)

Timber was also brought from Great Yarmouth and the total cost of the building came to around £36 - around £31,300 today.

The tower remained a strong presence in the city as the population of Norwich grew significantly from 1500 onwards.

In 1549, Robert Kett led an uprising in Norfolk and marched on Norwich where his army camped on the north-east side of the river, overlooking Cow Tower. 

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Kett had brought artillery which he used on Cow Tower, damaging its parapets, the topmost defences. 

Following the uprising, Cow Tower remained relatively unused for several hundred years except for use by merchants and was eventually passed to conservation groups for safekeeping.

Eastern Daily Press: A gardener mows the grass at Cow Tower, August 13, 1965A gardener mows the grass at Cow Tower, August 13, 1965 (Image: Newsquest)

Efforts to repair the tower in the 19th century involved using modern concrete which caused extensive damage when combined with erosion from the river. 

It stood unrepaired for more than 50 years before it benefited from a five-year renovation in the 1950s.

Cow Tower is now managed by Norwich City Council and has since been awarded its English Heritage status as a nationally important archaeological site.