This tribunal acts as a higher instance at the Apostolic See, usually in the grade of appeal, for safeguarding rights in the Church; it fosters the unity of jurisprudence and, through its own sentences, is a help to lower tribunals. It is also a court of first instance for cases specified in the law and for others committed to the Rota by the Roman Pontiff. The greater part of its decisions concern the nullity of marriage. In such cases its competence includes marriages between two Catholics, between a Catholic and non-Catholic, and between two non-Catholic parties whether one or both of the baptized parties belongs to a Latin or Oriental Rite. It also examines the fact of non-consummation in a marriage and the existence of a just cause for granting a dispensation. Causes for the nullity of priestly ordination are also within its exclusive competence.