Why Does Leonato Challenge Claudio to a Duel?

Leonato announces that, despite his great age, he challenges Claudio to a duel for the crime Claudio has committed against Hero by ruining her good name; Leonato states that he is not too old to kill or die for honor and for the love of his child.

Why does Benedick challenge Claudio to a duel?

Why does Benedick also challenge Claudio? He challenges Claudio in response to Beatrice's request; to prove his love for Beatrice.

How did Benedick challenge Claudio?

He then accuses Claudio of having killed Hero by his humiliation of her and challenges him to a duel. He tells Don Pedro that he will no longer be a member of his company and that Don John has run away. Benedick repeats his challenge to Claudio and leaves. They are disconcerted by Benedick's words and his challenge.