Dogs are simply one of the best things to happen to humanity in all of our history. The process of domestication began about 10,000 to 15,000 years ago, and is believed to have happened in more than one culture in parallel, in both Europe and Asia. Wolves and humans developed a symbiotic relationship at first, whereby we'd help out with hunting so that together, we could bring down bigger game. This developed into wolves sharing the warmth of our fires and starting to protect us. As wolves began to become our friends, humans began to breed them, and so they were selected for more desirable traits, such as being agreeable and trainable. Studies in foxes and wild dogs have shown that it only takes seven generations of breeding to radically alter how domestic-able an animal is, though of course this assumes a more precise process than the early farming societies would have had.
Since then, dogs developed in many directions, as humans required them to specialize for different tasks. We needed highly intelligent, quick dogs to herd sheep, and massive and very strong dogs to hunt bears. We needed small, wiry dogs to flush out rabbits and snuggly, little dogs to cuddle. That's how we got the number of dog breeds that exist today. These days, it's all about lifestyle, preferences, and personality - so tell us about yours, and we'll see what sort of dog you have!