Teodolfo Mertel, the last man to have been created cardinal without first having been ordained a deacon. He was ordained to the diaconate in 1858, a few months after becoming a cardinal.

In the historical practice of the Catholic Church, a lay cardinal was a man whom the Pope appointed to the College of Cardinals while still a layman. This appointment carried with it the obligation to be ordained to a clerical order, meaning that "lay cardinal" was not a permanent state, but a term in reference to a man who was appointed cardinal prior to taking on the clerical state corresponding to that appointment.

The current law of the Catholic Church is that a man must be first ordained at least a priest in order to be considered for appointment as a cardinal.

List of laymen who were created cardinals

NameYear created cardinalHighest clerical order received
Pope Paul III1493Pope
Pope Leo X1489Pope
Charles Borromeo1560Archbishop
Ferdinando I de' Medici1562Minor orders
Maurice of Savoy1607Minor orders
Francisco Gómez Rojas de Sandoval1618Priest
Ferdinand of Austria1620Minor orders
Giulio Raimondo Mazzarino1641Minor orders
Marino Carafa di Belvedere[it]1801Resigned before being ordained
Teodolfo Mertel1858Deacon

Discontinuation

In 1917, Pope Benedict XV promulgated the first edition of the Code of Canon Law, which included a provision that a man must be first ordained a priest prior to being considered for appointment as a cardinal.

According to The New York Times, Pope Paul VI considered making the French Catholic philosopher Jacques Maritain a cardinal in 1965.

See also