What is Mahr, and is it obligatory?

Mahr is a mandatory gift from the groom to the bride at marriage — money, property, or anything of agreed value — and it becomes the bride's sole and exclusive property to use as she wishes. It is obligatory in every Nikah, though there is no fixed minimum or maximum amount in most schools of thought; what matters is that both sides agree on it clearly before or at the time of the marriage contract. It can be paid immediately, deferred, or split between an immediate and a deferred portion, as agreed by the couple.