The term major orders was a part of the clerical terminology of the Roman Catholic Church before the Second Vatican Council. During the Counter-reformation, the Council of Trent issued a decree outlining seven orders of the clergy. The first four, the minor orders, had various liturgical functions and were conferred upon seminarians studying for the priesthood. The major orders were the final three, namely:

• The Order of Subdeacon,
• The Order of Deacon, and
• The Order of Presbyter, which consisted of priests and bishops.

A man could be admitted to the major orders only after receiving the minor orders. The vestments common to all those in major orders were the maniple, which was worn in liturgical functions until the Second Vatican Council, and the stole, which continues in use. Over the other vestments, the subdeacon and deacon would wear the tunicle or dalmatic. The chasuble was the vestment proper to both the presbyter and bishop.

The reason that these orders were considered "major" was that, with ordination to the subdeaconite, both the recitation of the Liturgy of the Hours and perpetual celibacy became mandatory. Those in minor orders did not have this obligation. Thus, e.g., an acolyte did not have to pray the Divine Office and could marry without Papal dispensation , should he leave the seminary. These lesser orders were seen simply as liturgical functions, which could be changed on the authority of the Church. This is exactly what happened in 1972, when Pope Paul VI suppressed the subdiaconate, and reconstituted the minor orders as lay ministries.