History of the Chihuahua
Although some history exists in regards to dogs similar to the modern-day Chihuahua, the origins of Chihuahuas seem somewhat shrouded in mystery. Some claim the dog originated in Mexico during ancient times, while others say that Chihuahuas were developed in China. Some long-ago Chinese practices included breeding animals into miniaturized versions of their ancestors.
Authorities have found a lot of answers relating to the chi's origin in old Mexico. The Olmec tribes were thought to be the "mother" of Mexico and were known to eat dogs during their time and by the age of the Toltec tribe, it became quite common to eat canine. There is evidence that they ate a plump, thick-necked dog with short erect ears and tail and it was clear it was bred for the table, being particularly for the noble. From Toltec carvings dating back to the 9th century, it is evident that they had a small dog which clearly looked similar to the modern day Chihuahua. This dog was known in that age and day as the Techichi and that breed is believed to be the ancestor of most of the Mexican and Central American breeds of canines. The Aztecs made full use of the Chihuahua-like dog and historical evidence shows that the dog appeared to be used in religious and other activities not related to companionship. In the early 1500s, the arrival of Hernando Cortes quickly halted the flourishing Aztec civilization. It was during this time that the Techichi was believed to become feral. What is known about the Techichi is that it was bigger than the modern day Chihuahua and had long hair. It is thought that the modern day Chihuahua originated from cross-breeding with Asiatic hairless dogs, but this has not been proven.
It wasn't until about the late 1800s that the Chihuahua that we know today made an appearance in the civilized world. A few were found in Mexico around 1850 and named after the Mexican state they were found in - Chihuahua. They remained rare until the early 1900s. Chihuahuas started gaining notoriety after being shown on television and in the early 1960s.
From The Complete Dog Book The American Kennel Club, 1997