Huh I read somewhere that Yorkies were first made popular as (they coined the phase lap dogs with them) during the Victorian era, as they were indoor "ratters" that exactly as said before some lady found interesting and thus like the Chinese imperial they were beyond domesticated.Bred for traits of people pleasing and dependence and an extreme want to be the center of attention from people. Amazing that Yorkies are one of the most aggressive breeds! I can see how having a lap dog in the days you actually needed the ratter instinct was appealing-your little snuggler that was multi-functional in jumping down and going crazy on a mouse that might wonder in to the room, kill it and then jump back to their person seeking approval and returning to sitting and continuing petting and grooming... I have a friend who's mother breeds Yorkies in England...I'll try to get an email response from her on the history showing that and I'll post it here for everyone to see, I just went from memory for this but I'm pretty confident as it was what turned me on to the breed in the first place...
this isn't the link but read this from here too
http://www.dogtraininghut.com/terrie...re-terrier.php
"You can say that the Yorkies developed into tough breeds because of their ancestors' reputation as rat-hunters. However, their size, and playful and bright character have actually captured the attention and affection of most pet owners. Most proud owners would boast that they have the great giants inside the bodies of these little dogs. If you want a small but terrible breed of dog, grab a Yorkie now! Just a friendly reminder, they would really need your attention and companionship than any other terriers."