Present day Norwich ( and Norfolk ) Terriers began life as a Show breed in 1932 when, as the drop and prick-eared Norwich Terrier, the breed was accepted on The Kennel Club Breed Register, but it is interesting to look at the breed's possible evolution.
Historically, small terrier-type dogs were popular amongst the farming and sporting community in East Anglia to use on rats and other vermin which infested the marshy region and its barns and crop stores. It is possible that some of these were the forerunners of the early Norwich Terrier.
During the 19th Century it is known that some of the Undergraduates at Cambridge University bought small terriers from a local dog dealer named Charles (Doggy) Lawrence. Cambridge, too, had plenty of vermin around, situated as it was on the banks of a river, just on the edge of the Fens, and these small terriers, which were often a tan or black and tan colour, were used mainly for catching rats around the Cambridge Colleges which were concentrated between the River Cam and the main street of the town. The dogs became known locally as "Trumpington Terriers", taking the name from the street where many students lived. The origins of those dogs are not really known but there was a suggestion that a small Irish Terrier ( smaller than the present-day breed) and a bigger type of Yorkshire Terrier had been used in their breeding.
Although the Club had wanted separate registers, The Kennel Club had insisted on two separate breeds being formed, each with its own separate name. It was decided that the more dominant prick-ears should keep the name "Norwich Terrier", and, after some debate, it was agreed by the Club, and after a Ballot had taken place, that the drop-ears should be known as the "Norfolk Terrier". After the formation of the Norfolk Terrier Club in 1964, the two breeds started on their separate ways.
The life expectancy of the Norwich Terrier is 12–16 years. While the Norwich Terrier is considered a healthy breed, there are some health issues for which responsible breeders do preventative genetic health testing, thereby reducing the incidences.
The Norwich Terrier does have a predilection for some health issues but studies to determine the exact mode of inheritance or the exact frequency in the breed are unknown or have not been conclusive. At present there are no disorders identified as "most important". Of secondary magnitude, cataracts are recognized as a disorder that has been reported sporadically and may be inherited. Also of a secondary magnitude there are instances of epilepsy, narrow tracheas, luxating patellas.