the principle of universalis successio ("total inheritance"), the heir inherited all rights and obligations of the deceased, including all their debts. Thus, becoming heir to a heavily indebted estate could lead to bankruptcy. Most people were granted a hundred days to consider whether to accept the role of heir. But children who had not been emancipated before death (sui heredes) and slaves who were simultaneously freed and appointed heir in the will could not refuse the role. Under the civil law, there was an assumption that all children of the deceased were heirs unless the testator specifically disinherited them (by name for male children, by general statement for female children). Under the praetor's law, this rule was extended to emancipated sons. Sometimes a testator would disinherit their children in order to avoid them becoming liable for any debts and then require the named heir to pass the property to the children through a fideicommissum. The will could also name substitute heirs, who would take over the role of the heir if the initial heir died before the testator or refused to accept the will. Justinian introduced a rule called "the privilege of inventory" (beneficium inventarii), according to which, if an heir began making an inventory of the estate within thirty days of learning that they were the named heir, then they would only be liable for debts from items contained in the inventory. Under the civil law, the heir claimed the estate through a hereditatis petitio ("claim of heirdom"). The praetor's law provided an alternative, the bonorum possessio ("order for possession of the estate"), where the heir was determined by the ruling of a magistrate. This ruling might be secundum tabulas ("in accordance with the will") or contra tabulas ("contrary to the will"). These two systems were very complicated, leading to efforts to simplify them and, eventually, they were merged. Invalid heirs Heirs had to be specific natural persons. It was impossible under Roman law to make a community, state, trust, or company the heir. The heir could not be any "unknown person" (incerta persona), e.g. a child who had not been born when the will was written. Foreigners (peregrini) could not be named as heirs. Under the Lex Julia de maritandis ordinibus of 18 BC and the Lex Papia Poppaea of AD 9, unmarried adults could not inherit or receive legacies and married adults without children could only receive