Minerva was the goddess of wisdom and creativity and she was very competitive. Once she was in a competition to win a city, and it was to see who could make something most useful. She made the thing that the gods said was most useful. It was olives. The other god made horses, but they were deemed not as important. So she won the city of Athens because her name in Greek is Athene.
There was another contest too. Minerva was well known for the fact that she was a brilliant weaver. There was also another woman, who was a mortal, named Arachne. She was also a brilliant weaver, and challenged Minerva to have a competition. Minerva changed herself into an old lady and visited Arachne. She gave her some friendly advice and said, “Do not challenge this god. She is powerful and she will beat you. Maybe, if you apologise she will have pity and forgive you." But Arachne got furious and shouted, “Let her come to me. I will have a match against her.” Then Minerva said in her disguise, “She comes,” and dropped her disguise. The girl was shocked but she stood firm. She would not back out.
They started the match and Minerva was sure that she would win. She knew that she was a talented weaver. Arachne, too, knew that she was a good weaver, but was not quite so sure. Minerva wove a tapestry showing how foolish she thought humans were and Arachne made one showing how foolish she though gods were, and she illustrated a few of the faults of the gods. Minerva did likewise, and Minerva was said to be the winner. Arachne was so sad that she died. Minerva took pity on her and said, “Have life.”
Then she turned into a spider. That is why spiders always weave.