The nowadays known as or widow´s allowance, as stated by the Justinian novellas, is an institution linked in its origins both to family law and in particular to the marital fourth in criminal law, thus are an important basis of the law of successions. In summary, this is a figure designed to solve the supervening poverty of the widowed spouse in the case of nuptials sine dote and nuptial donation, and at the end of Justinian's evolution, to resolve the absence of the widow's dowry instruments in the marriage.