This well-documented article revisits the issue of the inalienability and perpetuity of the waqf properties. The author demonstrates how the perpetuity of the waqf continues to have effect on the rights to endowed properties down to posterity, even after they lost their original form as waqf. Chahārdah Ma‘ṣūm Waqf in Teheran is a case in point. It is the Safavid royal family that created this large endowment and laid it down that the ruler of the time should be its administrator. In fact, the Safavid shahs designated a minister and treasurers to administer the endowment. The primary objective of the waqf was to provide sayyids with pensions. However, as the political confusion after the fall of Isfahan made an effective state control of the waqf more difficult, Ṭahmāsp II gave a part of the waqf land, located in Rey (south of Tehran), to heirs of a sayyid, Mīr Qanbar ‘Alī, as pension. At the end of the 18th century, working on the Qajar government aggressively, Mīr Qanbar ‘Alī’s descendants succeeded to obtain a royal decree offering them the position of mutawallī of the waqf property in addition to the already acquired right of pension. In the middle of the 19th century, they successfully filed a suit against actual occupants who lived in a piece of estate which had belonged to the waqf but was transformed into a substantially private property at that time. The fact that lawsuits over the disputed waqf property continued even into the middle of the 20th century, argues the author, mirrors the restrictive and eternal nature inherent in the waqf institution.