A cheerful mood is like a glorious sunny day. You feel as light as if the gods had made you out of bird's down. Nothing, no slight and no distress, can cloud your smile even if your master is stern and your back carries as many welts as a wild Libyan horse has stripes. 
Haetan walked along singing in his barbarian tongue. His dark face shone as though smeared with lard. His bare fit rose  and fell in time with the song. No man in Athens understood it, because Haetan holed from faraway country beyond the Euxine Sea. 
The day before, he had found an obol on the wayside among the bars roots of a plane tree. And only those who never had money of they own could appreciate his joy. An obol was an ocean of pleasures a slave could not dream of—an amphora of real wine, a couple of loaves of barley bread, a smoked eel or — a dish worthy of the gods — a handful of dried figs. Joys do not come alone. That morning, his master sent Haetan to town: to take a mule to the slaughterhouse. It was old, and staggered under a load. And the master was not one to feed a useless animal. Haetan was to bring back an obol for the hide. But he was no fool to hurry. It would be fun to drop by the town square and talk to other slaves who had been sent for provisions. He might find someone from his own country. He might go among the barbers and hear the latest news. If the master asked what took him so long, he would say the mule had been slow. 
And, indeed, the mule was in no hurry. It was also in a good mood: carrying no yoke around its neck and no load. Nor was anyone striking it to go faster. Luckily, it could not know that it was seeing sunshine for the last time. Its large mangy head was not bothered by thoughts of the shortness of life. It had no thought of human ingratitude. For nine years it had turned the wheel of a mill, and the past two, along with other animals, it had carried slabs of stone on its back, or parts of stone columns, or yellow wooden boards smelling of tar. It knew every groove and pothole in the road to the Acropolis. 
The path they were on that moment, trampled by the hooves of other animals, was unfamiliar. That was probably why the mule kept stopping and looking back at its driver. Or, perhaps, it had not seen a human sing before. It saw humans fight, beat and kick each other, and heard them howl from pain. No mule howled as loud and as plaintively. Then, the wretches would take it out on the beasts of burden, beating them with anything they could lay their hand on. 
Haetan sang and sang, and his song may have lasted right up to the slaughterhouse if he had not come upon a stranger standing by the wayside, round-faced, his bare feet placed far apart. Haetan sensed the man's wish to pick a quarrel, ended his song and stopped in his tracks. He did not know this snubnosed fellow with a knobby forehead. Maybe he did not like Haetan's song or maybe he wanted to take away the mule.
 "Mule, where are you leading the slave?" the stranger asked. 
The question frightened Haetan. Why did the man call him a mule? Was he blind? Or had the gods denied him brains? He decided it was best not to show his fright and surprise, and replied politely: 
"I'm Haetan, slave of Hylippos, who ordered me to take the mule to the slaughterhouse. It is old and useless." 
"Then you're twice a fool," the man replied. "Aren't you sorry for the animal? Let it go its way, and you go yours."
"What about the obol for its hide — I have to bring that back to my master." 
The stranger pulled out a little leather purse and stuck his fingers into it. But his face grew long. 
"Strange," he said. "I had an obol. Where is it? Did I lose it?"
Unthinkingly, Haetan spoke up:
 "Is this yours? I found it yesterday under a plane tree."
 "I don't think so," the stranger replied, rubbing the back of his head. "Besides, how can we know? I didn't mark it. And I'm sure I had it this morning. But where could I have lost it? — Ah, I forgot. I gave it to a beggar." 
"You couldn't have given him a whole obol," Haetan exclaimed unbelievingly. 
The stranger understood what Haetan meant: 
"Yes, my clothes deceive you, I'm not rich. I can swear to that. And the obol created so many temptations I decided to get rid of it as quickly as I could. Besides, the beggar had a game leg. He told me he was from the Mount Laurium mines. A rock had crushed him and the leg had to be amputated. His owner gave him his freedom and chased him out of the house. Who wants a lame slave?" 
Haetan's cheerful mood vanished. He had heard of the Mount Laurium silver mines. Slaveowners hired out slaves for an obol a day to work in the mines. The beggar had been lucky for getting his freedom. Others died within a year or two — from the flogging and the bad air. Was that why the stranger had called him a mule — for unprotesting obedience without a thought for the future? When he grew old, like this mule, he'd be thrown out of the house as useless. If his hide had had some value like the mule's, they'd have taken him to the slaughterhouse.
"You gave the beggar an obol," said Haetan, "and I'll give mine to my master. Let the mule go his way, I'll go mine." 
Haetan walked away in the direction of the town square. The stranger glanced at the mule, shrugged his shoulders, stuck his purse back under his belt, and set out on the slave's heels.

 In the morning of the following day the builders of the Parthenon saw a mule with no burden walking in front of a few dozen beasts pulling a large slab of marble uphill for Phidias himself to sculpt into a statue. (Parthenon, literally temple of the virgin, was the temple of Athena Parthenos on the Acropolis in Athens, regarded as the first and finest peripteral Doric temple. It was erected in the time of Pericles).  No one goaded it. The mule kept looking back, as though to make sure the other animals were following. It shook its head from time to time, seemingly in approval of their diligence. Reaching the peak of the hill, it waited for the other mules to be relieved of their burden, and returned downhill, only to accompany them up again. 
The tale of the strange mule spread quickly. The voraciously inquisitive barbers left their clients and came to the foot of the Acropolis to see for themselves. The town square, which usually teemed with people at that time of day, was half empty. Only the traders were left, wondering where their customers had gone. Someone struck the bell announcing the arrival of fresh fish, but even that did not call back the Athenians, always eager for a spectacle. 
"It's Hylippos's mule," someone shouted. 
"Hylippos got an obol for its hide," someone else said. "It must have come back from the dead." 
"See it strut — like an overseer!" a third cried out. 
A snubnosed man with a knobby forehead climbed atop a slab of white stone evidently intended for a statue. It was the stranger who had talked Haetan into ransoming the mule. Haetan, who was among the builders of the Parthenon, recognised him, and was pleased to see him again. He was proud of what he had done. Had it not been he, Haetan, who ransomed the animal instead of taking it to slaughter. He had not grudged his only obol. And had not let the fear his master may discover his trick stop him. 
The man on the white stone slab raised his hand, and silence fell. 
"Citizens," he said. "The gods have performed a miracle that no city in Greece or elsewhere has ever seen before. Look at the mule. It has scales and sores on its back. For two years it carried the rocks and boards you are building the Parthenon with. When it was allowed to go free, it came here on its own. I can swear it wants to cheer us up by its example. There is no temple like the one rising here on the Acropolis. The world has seen nothing like the statues and reliefs that are being made by Phidias and his pupils. How true to life they are! How vigorously fresh! Injustice must not taint their beauty or the whiteness of these columns! Is our state incapable of feeding a mule that lias grown old building the temple of Athena?" 
The crowd roared in approval. 
Another speaker elimbed upon the slab of rock, a man of about forty, with a handsome, intelligent and imperious face. 
"Quiet," the crowd roared again. "It's Pericles. Pericles, speak!" 
"Athenians," Pericles said. "I do not intend to make a speech. My friend Socrates has done it for me. (Socrates, a Greek philosopher whose young years coincide with the time of Pericles. Though surrotsnded by young noblemen who revered him for his sharp mind and his knack of exposing false knowl edge, he had lived in poverty. In 399 B.C., when an old man, Socrates was accused of impiety and of corrupting youth, and was sentenced to death).  Let the public crier announce that Hylippos's mule is under the protection of the state. If the animal should ever wander into a field or a granary, it must not be chased out until it has eaten its fill, and, besides, citizens are to contribute to the treasury so that on holidays the mule should be assured a feast — like our veteran athletes. As for the slave who saved the mule — I shall buy him from his owner and grant him freedom."