In the Roman Catholic Church, a judicial vicar or episcopal official (Latin: officialis) is an officer of the diocese who has ordinary power to judge cases in the diocesan ecclesiastical court. Although the diocesan bishop can reserve certain cases to himself, the judicial vicar and the diocesan bishop are a single tribunal, which means that decisions of the judicial vicar cannot be appealed to the diocesan bishop but must instead be appealed to the appellate tribunal. The judicial vicar (or officialis) ought to be someone other than the vicar general, unless the smallness of the diocese or the limited number of cases suggest otherwise. Other judges, who may be priests, deacons, religious brothers or sisters or nuns, or laypersons, and who must have knowledge of canon law and be Catholics