In Tobit, one of the books of the Apocrypha, the hero Tobias sets out on a journey to call in a loan owed to his father, who has gone blind. He will return with a bride and a cure for his father’s blindness. But he sets out on the journey with a young man — who he does not recognize as an angel — and a faithful dog.

Well, sort of. There are several versions of this apocryphal book. In the version that was current among Greek-speaking Jews, there is a dog. In the versions that circulated among Jews closer to Jerusalem, there is no dog. That’s because in many of the nations in ancient times, as well as Jews who had become acculturated to the Greek speaking world, dogs were acceptable as pets and companions.

It’s hard to say just when dogs and humans became boon companions. Archaeologists w…