* Ancient times: Dogs have been assisting humans for thousands of years, primarily for hunting and herding. Some evidence suggests dogs were used to help people with disabilities in ancient times, such as pulling carts for those with mobility impairments.
* Medieval Europe: Dogs were increasingly used to guide blind people, with documented accounts from the 16th century onwards.
* The 19th century: The development of specialized training methods for dogs led to more systematic use for various tasks, including assisting deaf individuals and those with epilepsy.
* The 20th century: The "Seeing Eye" program in the United States (founded in 1929) played a pivotal role in formalizing the training and use of guide dogs for the blind, leading to widespread acceptance and recognition.
It's important to note that the concept of "service dog" as we understand it today, with legal protections and specific training standards, is relatively modern. The modern service dog movement has its roots in the early 20th century, building upon centuries of dog-human partnership.