So this is the way I heard it. More or less.
After his Enlightenment, Siddhartha was walking along a path in a forest. He didn’t have a goal and he wasn’t concerned with the weather: if it was hot, he sweated, if it rained, he got wet. He was untroubled, calm, serene.
In fact, he was so untroubled that it was obvious to anyone around him. He met a man traveling the opposite direction.
“Excuse me,” the man said, “are you a sadhu, a saint?”
“No,” Siddhartha said, “I’m not. Being a saint doesn’t really lead to peace of mind anyway.”
“But you’re … are you a God?”
“Hardly. I’m just a man. I don’t know if there are any gods, but I’m certainly not one.”
“Well… but you seem so different. What makes you so different?”
Buddha thought about it. It couldn’t really be explained, of course, but still the man deserved an answer.
“I am… awake.”
About 2500 years ago there was a city-state called Kapilavastu in what is now called Nepal. According to tradition, a man named Sudhodana was its king, although archeology and history suggest that it was an elected post in something much like a republic. Sudhodana had a wife, who we know as Mayadevi, which means something like “Enchanting Angel.” She was pregnant, and as the traditions of that time and place required, she was traveling to her home to have their child, when she went into labor and was taken to the shade of a tree in a place called Lumbini. Her child was born there, a son, who was named “Siddhartha”, “the one who achieves his aim”. Mayadevi died shortly afterward.