Why was John Donne arrested after his marriage?

He was arrested because he married a woman against the wishes of her father and other relatives. He was released when the marriage was proved valid. After his release, he got both the man who had married them, and the man who had witnessed it out of jail as well. They had all been arrested because of the wedding. Donne also lost his job over it, and the family was destitute for quite a while.