The sharing economy and the legal devices clustered about it became increasingly distinct from ownership vested in one person, which would be at the heart of the sense of property developed in modern law, beginning in the Enlightenment. Overlapping rights were too confusing and liable to keep property from transactions in the increasingly important market economy. The continuity between father and son that Bartolus saw at the heart of the family became harder for others to envision.

One of the central devices for attempting to keep property together and provide for family continuity was the fideicommissum, which was a trust adapted from elements of Roman law. Fideicommissum combined substitution of heirs in agnation, so male lines did not die out, with prohibition of alienation of key family properties extra familiam (making them effectively inalienable). Legal experts had difficulties allowing the Roman fideicommissum, limited to four generations, to endure indefinitely, so they demanded some precise language in testaments of other instruments that established fideicommissa, including clear statement of a testator's intent that property not leave the family, which was at least seen as a laudable goal of legal property management.