Alexander the Great and, later, the Roman emperors were also fond of dogs. Because the Greeks and Romans traded with the Egyptians, dogs became popular with Hellenic aristocracy for a variety of purposes. Unlike the Egyptians, who prospered in semi-isolation, the Greeks and the Romans were products of the very heavily populated and mercantile-minded Mediterranean and Middle Eastern cultures. Life was competitive and land came at great cost.

Learning from the Persians and their other warlike neighbors, the Greeks began to use two types of dogs. One was large and massive in build, with a large, broad face, and was known as the Molossian. The other, known as the Laconian Hound, was also large, but had a rather pointed snout, and was faster and sleeker. Aristotle was a fan of both dogs, saying that the Laconian female was gentler and smarter, but by no means fit for war, and that the Molossian was the dog of choice.

The Molossian was named for the northern Greek tribe that had made it well-known. The Molossian of Alexander the Great's time is the ancestor of today's Mastiff, which for centuries was the ultimate dog of war — large, strong, fearless, and smart. The Greeks and then the Romans used these beasts in war for something like a cavalry charge. The Laconian Hound was developed, it is believed, in Sparta. It was fast and brutal, but of a sleeker build than the traditional Mastiff.

The first literary classic pairing of a man and his dog comes from the Greeks. Dating back to one of the first classic pieces of literature known and studied for centuries, The Odyssey features the story of Odysseus, warrior of the Trojan War, attempting the long, treacherous, and adventurous journey home. After many years away from his farm and kingdom, the hero of the story is not recognized by those people who knew him long ago. Despite his claims, he is only believed when his faithful hound — by then old and impaired — crawls to his master, for whom he has been faithfully waiting. Upon greeting him, Odysseus's dog dies, wagging his tail, happy at his master's feet.

If dog was man's best friend in Greece, another dog was the mother of Rome. According to myth, two men fought over the founding of Rome: Romulus and Remus, who had been raised by a wolf, suckling on her milk. It was the Romans who first outfitted their war dogs with thick leather collars, studded with sharp metal blades to deter other attacking dogs. Dogs were instrumental in Rome's rise. As its famous roads were built and expanded, guard posts along the way were manned by small militia and hosts of guard dogs. The Romans also used their large dogs as beasts of burden. It was not unusual to see dogs, along with cattle, oxen, horses and ponies, pulling carts of all sizes from all different parts of the empire.