The Yorkshire terrier was born in the first half of the XIX in the north of England, being the result of a rigorous genetic selection with heterogeneus specimens, so it's not a breed made by the natural selection. This is the great result of making a breed with glamour, bearing and full of that terrier spark.

The obscurantism around the Yorkshire Terrier's appearance as a breed is cause by the mutation by the first crosses of the breeders, and over all because there's no documentation over them. In the last years of the XVIII century, in 1785, there were some changes in the social structure because of the Industrial Revolution, started in England and expanded to Europe later. In Great Britain you could notice it in the textile industry, specifically in Yorkshire, where a lot people from the poorest parts of England and Scotland moved. So that's why this breed is called like that, but we must have in mind that the inital crosses came from the northen parts of Great Britain.
 

York (Eboracum in the past) is a city in the north of Yorkshire, where the Ouse and Foss rivers converge. In the century I a.C the place was occupied by the romans, who gave it the name Eboracum and they turn it into one of the most important military base of the Roman England. The Emperors Lucio Séptimo Severo and Constancio I, and Constantino I was proclaimed emperor in the year 306. In the VII century, the city erected in the capital of the Anglian kingdom of orthumbria.

Over the year 625, York was appointed the Holy see, and over the VIII century it was a famous educational centre. Conquered by the vikings in 867, it turned to a vassal state of the western saxons. In the Middle Ages, York was a prosperous harbour and a merchant city. In 1644, during the English Civil War, York gave up in front of the parliamentary after the Marston Moor battle. The economic decline, caused by the decadence of the wool commerce, stopped in the XIX century, when York started to develop like an important rail centre.

The name of the city is a derivation of the danish word "Yorvick". In the coal mines they used to hunt mice a little dog with upright ears called "Black And Tan Terrier", today called "English Toy Terrier". This breed could be used to create the Yorkshire Terrier. They were used as well in the textile industry to hunt mice and help with the dissapearance of the wool.

The lower classes in England were not allowed to own dogs, they only could have small dogs, used mainly to kill rats and other animals, like the Waterside Terrier, which was described as: "a small dog with long hair, blued black, with a weigh between 3 and 9 kg., but usually it was around 4.5 kg" This was crossed with the Manchester Terrier, with black and toasted silky hair.
 

Its origins are not entirely clear, as is known are the summaries of the stories passed from mouth to mouth, among breeders, enthusiasts and lovers of the breed.
 

There is different hypothesis about the origyn of the breed; one of them is that the workers of the north of England tried to hide their secret and succed to prevent to the others to get rich creating the same type of dog, maintaining that it was likely that the Scots who used to go to the Yorkshire wool industries carry with them various types of terrier, including Syke Terrier, Clydesdale Terrier and the Paisley Terrier.