in Saunders v Vautier enabling all of the adult beneficiaries to draw special legal agreements together to override any historic provisions. See rule against perpetuities – each rule varies by jurisdiction. Mortmain was a key underlying interdiction in legal history, contextualising much early case law. The decision of Thornton v Howe held that a trust for publishing the writings of Joanna Southcott was charitable, being for the "advancement of religion". This decision is often held up as setting the bar extremely low in determining whether a charity is for the advancement of religion. At the time of her trust-making the statutes against mortmain were in force and having not met the narrow, high-authority formalities for such a trust to be valid it was void, rather than imbuing it with special privileges in relation to taxation and viability. Identifying the trust within the general run of mortmain forbiddance shapes the case's reasoning (ratio). Etymology William Blackstone wrote, in 1765, "The reason of [this] appellation Sir Edward Coke offers many conjectures; but there is one which seems more probable than any that he has given us: viz. that these purchases being usually made by ecclesiastical bodies, the members of which (being professed) were reckoned dead persons in law, land therefore, holden by them, might with great propriety be said to be held in mortua manu. [in dead hands]." See also Cestui que Statutes of Mortmain Waqf, the Islamic equivalent of mortmain Footnotes Legal history of England Medieval English law Religion law