Is the marriage of the People of the Book to one another, according to their own laws, considered fornication?

Scholars differed regarding the marriages of disbelievers. Imam Malik held that they are invalid, while the majority of scholars considered them valid. The majority based their view on the fact that the rulings of a valid marriage pertain to them, such as the occurrence of divorce, mahr (dowry), qasm (equitable division of nights among wives), and ihsan (chastity). They added that the Qur’an attributed women to disbelievers, which indicates the validity of the marital relationship, and that the Prophet, peace and blessings be upon him, was born from a marriage, not from fornication. Sheikh al-Islam Ibn Taymiyyah mentioned that the marriages of disbelievers are referred back to their customs; whatever they consider a marriage is permissible to uphold.