In Roman Catholicism and certain other Christian churches, the sacraments are a key and essential part of the faith. In Roman Catholic teaching, the sacraments serve to perpetuate the union of God and humankind. They are “the visible form of an invisible grace,” as St. Augustine famously described them. Roman Catholicism celebrates seven sacraments: baptism, the Eucharist, confirmation, reconciliation (confession), marriage, anointing of the sick, and holy orders. Some, such as baptism, confirmation, marriage, and ordination, are generally only to be received once in a Roman Catholic’s life. For others, such as the Eucharist and reconciliation, frequent participation is encouraged.