What is Contra Formam Collationis?

Legal Definition
In English law, contra format collations was a writ to recover donations in a situation where a man had given perpetual alms to a religious house, hospital, school, or the like, and the governor or managers had alienated the lands, contrary to the intention of the donor.
-- Wikipedia
Legal Definition
In old English law. A writ that issued where lands given in perpetual alms to lay houses of religion, or to an abbot and convent, or to the warden or master of an hospital and his convent, to find certain poor men with necessaries, and do divine service, etc., were alienated, to the disherison of the house and church. By means of this writ the donor or his heirs could recover the lands. Reg. Orig. 238; Fitzh. Nat. Brev. 210.
-- Black's Law Dictionary