Rashi on Genesis 1:16/רש"י על בראשית א׳:ט״ז

1המאורות הגדולים THE GREAT LUMINARIES — They were created of equal size, but that of the moon was diminished because she complained and said, “It is impossible for two kings to make use of one crown” (Chullin 60b).

2ואת הכוכבים AND THE STARS — Because He diminished the moon, He increased its attendant hosts to mollify it (Genesis Rabbah 6:4).