Lay 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 Holy orders in the [Catholic Church|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
| Name | Year created cardinal | Highest clerical order received |
| Pope Paul III | 1493 | Pope |
| Pope Leo X | 1489 | Pope |
| Charles Borromeo | 1560 | Archbishop |
| Ferdinando I de' Medici | 1562 | Minor orders |
| Maurice of Savoy | 1607 | Minor orders |
| Francisco Gómez Rojas de Sandoval | 1618 | Priest |
| Ferdinand of Austria | 1620 | Minor orders |
| Giulio Raimondo Mazzarino | 1641 | Minor orders |
| 1801 | Resigned before being ordained | |
| Teodolfo Mertel | 1858 | Deacon |
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.