The outlines of the following story appear in Procopius’s Wars (II.12.8).
The Assyrian king Abgar V governed a region that had its capital at the city of Edessa. The exact dates of his birth and death are not known, but he apparently ruled from around 4 B.C. to 7 A.D. and again from about 15 A.D. to 30 A.D. He was an ally and friend of the Roman Empire; the emperor Augustus knew him well and valued his counsel on Near Eastern affairs.
Augustus liked him so much, it seems, that he was unwilling to let him leave Rome after he concluded a mutual assistance treaty with the Romans. Every time he would bring the matter up, Augustus would find a new excuse for putting him off. Finally Abgar thought of a way to make his point in a way that would resonate with the distracted emperor.
Abgar had taken a liking to hunting and knew the forests and fields of the Italian countryside well. He went out for an extended hunt and captured a variety of animals alive. He also dug up some dirt and sod from the various parts of the region where each animal made its natural habitat. All of this–the animals and the dirt–he brought back with him to Rome.
When Augustus was at the hippodrome watching the spectacles there, Abgar paid him a visit with his baggage of live animals and earth samples. He showed the emperor what animals he had, and the earth from where each came from. He then had the different samples of dirt placed in different parts of the arena of the hippodrome, and turned loose all the animals there also. The animals wandered around, but each one eventually stopped at where it found the soil of the region where it used to live.
So it is that every living thing is drawn to the place where it was reared. Augustus, watching this entire affair closely, was deeply impressed. He marveled at how Nature imparts such significance to the soil of an animal’s native land, that it would instinctively be able to find it in a foreign setting. The lesson was not lost on the emperor. Abgar now said to him:
Master, what do you think my own thoughts are, who has a wife and children and a kingdom, small indeed, but in the land of my fathers?
The emperor was moved by this statement and saw that he should let Abgar return to his home. He also told the Assyrian king that he could ask him for whatever wish he desired, and said that he as emperor would grant it if it were within his power. Abgar asked that the Romans should build a hippodrome in the city of Edessa.
When Abgar returned to his capital, his countrymen asked him if he had brought with him anything of value from the Romans. He told them of the plans to build the hippodrome, and how it would be an arena for entertainment. He told the people of Edessa that, by building the structure, he was providing them “pain without loss, and pleasure without gain.”