Ephoreia, one of the principal forms of monastic trusteeship in the Byzantine empire, appears for the first time in texts around the year 1000. Despite its prevalence, like many post-Justinianic legal developments, ephoreia is not mentioned in the normative legal codes of the Middle Byzantine period, including the Basilika. A previously overlooked passage from the eleventh-century casebook known as the Peira, which was compiled by an anonymous redactor from the verdicts and legal treatises of the jurist Eustathios Rhomaios, mentions ephoreia in the context of how much time must elapse before a possessor of property acquires ownership. This mention of ephoreia in the Peira is one of the earliest, if not the earliest, appearance of the term as describing monastic trusteeship. The reference is an important example of a contemporary legal development without a basis in Roman law which was accommodated within the contemporary legal regime.