Apollo's Oracle at Delphi - Ancient Greek myth
Apollo decided he needed an assistant, a wise woman, an oracle. An oracle, in ancient Greece, was someone who could see the future. But Apollo did not want any old oracle to speak for him. He wanted a real one. But there weren't any real ones, not really. The oracles he had met always had vague answers.
For example, if you asked an oracle if you should plant your garden tomorrow, they might say "the frost will be gone if the gods will it." Not really helpful.
Apollo had the power to magically make someone truly see the future, just as he could. But Apollo didn't want to take the fun out of things. So Apollo set some ground rules for his oracle. He would use his magic to allow her to truly see the future. Apollo's rules stated that she had to tell the truth, but she could not be too specific. That would allow the possibility of misunderstanding. That would made it fun!
Apollo magically turned a young priestess into a real oracle. He magically built a special temple for her home. He magically told a few people here and there about his wonderful oracle.
It did not take long for the word to spread. People came from all over to ask Apollo's oracle a question. People had heard she could really see the future and could only tell the truth.
One day, a weary king came to the temple. He asked Apollo's oracle if he would win the battle. She smiled and told him a great king would win the battle. That was exactly what he had wanted to hear. He went away happy, leaving many gifts for the oracle behind him.
When he led his men into battle, they lost. The king was killed. But people still flocked to Apollo's oracle. They knew she had told the truth. She had to tell the truth. What a pity the king had not listened.