Sale or purchase of spiritual gifts or of positions of power in religious hierarchies. This may include buying or selling of sacraments or sacramental ordinances, such as the exacting of payment for baptism, for the eucharist, and for the conferring or receiving of holy orders.
Named after Simon Magus who offered money to acquire the gift of laying on of hands. Of special concern during the Middle Ages in the buying and selling of ecclesiastical preferment, even involving the pope. This was one factor contributing to the Protestant Reformation.
Of considerable historical importance, especially within Christianity. But no age or country can be said to be completely free from it. When it is suppressed in its more obvious forms it takes a disguised form and becomes more difficult to overcome. For example, the sale may be disguised as a donation. It could be argued that some currently advertised courses to acquire spiritual or psychic powers (including 'siddhis') are a form of simony. Similarly the donation of funds to a spiritually oriented group in effective exchange for a position of power within that group can be considered in the same light.
In situations where the priesthood is impoverished, the receipt of money for sacraments offered one of the only sources of income.