Women in the Anglo-Saxon kingdoms appear to have enjoyed considerable independence, whether as abbesses of the great 'double monasteries' of monks and nuns founded during the seventh and eighth centuries, as major land-holders recorded in Domesday Book (1086), or as ordinary members of society. They could act as principals in legal transactions, were entitled to the same weregild as men of the same class, and were considered 'oath-worthy', with the right to defend themselves on oath against false accusations or claims. Sexual and other offences against them were penalised heavily. There is evidence that even married women could own property independently, and some surviving wills are in the joint names of husband and wife. Marriage comprised a contract between the woman's family and the prospective bridegroom, who was required to pay a 'bride-price' in advance of the wedding and a 'morning gift' following its consummation. The latter became the woman's personal property, but the former may have been paid to her relatives, at least during the early period. Widows were in a particularly favourable position, with inheritance rights, custody of their children and authority over dependents. However, a degree of vulnerability may be reflected in laws stating that they should not be forced into nunneries or second marriages against their will. The system of primogeniture (inheritance by the first-born male) was not introduced to England until after the Norman Conquest, so Anglo-Saxon siblings – girls as well as boys – were more equal in terms of status.