The nature of the covenant requires that the two participants be one man and one woman, that they be free to marry, that they willingly and knowingly enter into a valid marriage contract, and that they validly execute the performance of the contract. On the exact definition of each of these steps hinge all the arguments and technical points involved in annulments, and annulment disputes (e.g., one of the most famous, that of Henry VIII). Catholic Canon law regulates the celebration of marriage in canons 1055–1065.