Sayyidah Aishah (may Allah be pleased with her) said that the Prophet (peace and blessings be upon him) said: "A woman should not marry without the permission of her guardian. If she marries, it is void, it is void, it is void. If he consummates the marriage with her, then the woman is entitled to the dowry (mahr) because of the intercourse he had with her. If the guardians dispute among themselves, then the ruler is the guardian of the one who has no guardian."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 13655