A Pontifical High Mass in the Roman rite before the changes brought forth by Vatican II is a Mass celebrated by a bishop that does not omit any elements which are omitted in the pontifical low mass , such as incense. A Pontifical Low Mass is almost identical to a priest's low Mass, except for a delay in putting on the maniple until after the prayers at the foot of the altar.

The Pontifical High Mass really is considered historically the basis for the whole liturgy and its evolution, especially since there were no masses that were sung by exclusively priests in the early church.

It is very different from a mass celebrated only by a priest. Almost the entire first half of the mass is said from the cathedra, which sits on the left side of the altar. Instead of saying "Dominus vobiscum" (the Lord be with you), the bishop says "Pax vobiscum" (peace be with you).The bishop also wears additional garments above and beyond what the priest wears:

• The dalmatic, the outer garment of a deacon, is worn under the bishop's chasuble to show that he has the full powers of the sacrament of Holy Orders.

• The tunicle, the outer garment of the subdeacon, is worn under the bishop's dalmatic to show the fullness of the major orders. Since the 19th century it looks almost exactly the same as the dalmatic.

• The mitre, the Bishop's hat.

• The crosier, the Bishop's staff.

• buskins , a special form of socks, along with sandals a specially decorated form of footwear, in the shape of loafers.

• a pectoral cross

• liturgical gloves

• A metropolitan archbishop wears a pallium over the chasuble which shows that his special authority has been granted by the Pope, although he technically has very little authority over suffragan bishops.

When the Bishop sits down at his throne, a special silk cloth is placed in his lap.

Before Vatican II, the Pope's pontifical mass when he celebrated at St. Peter's was even more elaborate. It included the gospel and epistle being sung in Greek by a Greek-Rite deacon and subdeacon, because St. Peter's is actually supposed to be the Greek church in Rome (the Pope's real Cathedral being the Basilica di San Giovanni in Laterno). During the liturgy these Greek priests observe the rules of their rite, such as a profound bow instead of kneeling. Fanfares are sounded on silver trumpets at the elevations. The Pope drinks the consecrated wine, which Catholics believe is the blood of Jesus, through a straw. Also pieces of the bread before it becomes the body of Christ is tested by a deacon before the Pope to check to see if it is poisoned.