(From Latin simonia, via French. Eponymously derived from the name of Simon Magus, viz. Acts VIII,18ff.)
In Christian dogma, the sin of bartering, selling or buying holy offices or sacraments. An act of corruption, its name is derived from the Biblical hubris of Simon Magus, who offered to purchase the Holy Spirit from the apostles.
In the middle ages, the Papacy decried the practice of lay investiture as simony (the Investiture Crisis). Later, during the Reformation, the sale of indulgences (documents absolving the buyer of sin) by the Roman Catholic Church, as if absolution were a commodity, was used to justify Protestant denial of papal authority.
Simony applies not only to the sale of ecclesiastical rank, but extends to any sort of quid pro quo with regard to spiritual values, including the sale of sacraments or of church jurisdiction. However, votive gifts, legacies and tithe are not considered simony.
According to Canto XIX of the Divina Commedia of Dante Alighieri, simonists, upon dying, find themselves in the Eighth Circle of Hell, each simonist held head down in a rock with only his feet protruding, and perpetually being burned by an eternal flame.