A Protestant baptism is held to be valid by the Catholic Church if given with the trinitarian formula and with the intent to baptize. However, as the ordination of Protestant ministers is not recognized due to the lack of apostolic succession and the disunity from Catholic Church, all other sacraments (except marriage) performed by Protestant denominations and ministers are not recognized as valid. Therefore, Protestants desiring full communion with the Catholic Church are not re-baptized (although they are confirmed) and Protestant ministers who become Catholics may be ordained to the priesthood after a period of study.