Once upon a time a girl named Bastet grew up with cats. She loved cats so much that she owned every one of them within where she lived. Every cat obeyed her every command, and people called her the cat goddess because of her love of cats and how they obeyed her.
Later on in her life she actually became the cat goddess. She was worshiped at the city of Bast by cats. She created that city by taking the first four letters of her name and building a temple in it where only cats were welcome. Even though it was her city she still worshiped there because of the cats that lived there.
Since cats are the guards of the Underworld they are usually guard at night and are connected to the moon because they love nighttime so much and are loyal to the moon. Since Bastet was the cat goddess she too was connected to the moon and was allowed to control it. So she made Egypt dark for six months and then after six months it was normal again. She followed that plan until she died. After she died all the cats that were most loyal to her died with her and are buried with her as well. The cats have guarded her in the after life.
People all around Egypt knew about her one way or another. Most people knew her because of the light change. After she died, people always knew her as the eye of the moon and the cat goddess.