Seminarians who enter into the theological, or major seminary, are in their final preparations for ordination to the transitional diaconate, and to the priesthood. The major seminary program is four years in length, and during this time, seminarians engage a full line of academic and spiritual programs to prepare them for ordained ministry in the Church.
While in the major seminary, a seminarian receives three ministries. These ministries come at different intervals, and depend upon the particular seminary as to when they are administered. Oftentimes, these ministries are conferred to the seminarian by a bishop.
The ministry of lector prepares the seminarian to proclaim God's holy Word, and is the primary function of his ministry as a transitional deacon. The ministry of acolyte invites the seminarian to more deeply contemplate his role as one who is the giver of Christ's Body and Blood at the holy Mass, and eventually, the one who is given the power to confect the Holy Eucharist by the power of his priestly office. The ministry of candidacy announces to the seminarian's sponsoring diocese and to the entire Church that he has been chosen for ordination.
Before the seminarian can be ordained to the priesthood, he must first serve as a transitional deacon. The difference between a permanent deacon and a transitional deacon is that the permanent deacon will permanently serve in the role as deacon. A transitional deacon is in "transition" from diaconate to priesthood, and will serve in the role of deacon anywhere from six to twelve months before his priestly ordination.