The Prophet (peace and blessings be upon him) said: "A woman is not to be married without the permission of her guardian; if she is married (in that way), that marriage is void," he (peace and blessings be upon him) said this three times, "and if he has had intercourse with her, she is entitled to the dower. If the guardians dispute, then the ruler (sultan) is the guardian of the one who has no guardian."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 13712