A marriage is never considered legal if it is incestuous or bigamous. In addition, a marriage can be declared invalid via annulment if:
- One party is under the age of 18 at the time of marriage
- Either party was already legally married
- Either party was of unsound mind or unable to understand that the nature of the marriage and obligations that came with it
- Either party got married as a result of fraud
- Either party was forced into getting married
- Either party physically incapacitated