Board Thread:Suggestions forum/@comment-25555112-20151126170511/@comment-26322120-20151217012612

There was an island that Sauron was captured at and he convinced most people there including the king that Eru was an idea made by the valar to control them and that Melkor was the true God so they stopped going to the Meneltarma ( a place of worship to Eru) and built a temple to Morgoth where they sacriced people. Suddenly disease and malice spread and the great bliss ended and great storms came, then Sauron concinved the king to send a fleet against Valinor. After that many things happened, one of which was Manwe complaing to Eru and Eru sinking the island. Thats what Tolkien says at least...

This was a very short and incomplete summary, for more info read the Alkabeth (like me) of see here.