The Eucharistic Prayer(s)
The Eucharistic Prayer, already begun with the Preface, continues with what we usually think of when hearing one speak of “The Eucharistic Prayer,” viz., the prayer through which the bread and wine become the Body, Blood, Soul and Divinity of Jesus, though still looking like bread and wine.
There are a variety of Eucharistic prayers (called also an Anaphora, meaning offering) from which the priest can choose.
Eucharistic Prayer I, called also, The Roman Canon (canon speaking of its fixed nature) was the only Eucharistic Prayer for centuries. It is “Roman” because it reflects how the prayer was done at Rome. Before Pope St. Pius V put together the missal used from 1570 until about 1970, different locales had different ways of saying Mass. The Missal of Pius V made the liturgy uniform throughout the Church, with a preference for the Roman practice. I will use The Roman Canon on greater feasts, on days when special prayers are added for the day’s celebration, or when the saint of the day in named in the prayer (more on all this later, when I will take a closer look at this prayer.)
Eucharistic Prayer II is the shortest. This is based on the Apostolic Tradition, a text from the third century, which was an early example of how Christians worshiped. The GIRM instructs that Eucharistic Prayer II, “is more appropriately used on weekdays or in special circumstances” (365b). For this reason, I do not use Eucharistic Prayer II at Weekend Masses. (One priest I know said, “If you hear me praying Eucharistic Prayer II on a Sunday, call 911, because I must be very ill.”) I will use it on weekdays (outside of Lent and Easter), when no saint is celebrated.
Eucharistic Prayer III was one that was created at the time of the Missal of St. Paul VI in the 1960s. It is in the spirt of the older forms of the prayer. I use this on most weekends outside of Lent and weekdays when a saint is celebrated, because this prayer offers the option of including the name of the saint of the day, which the other forms of the prayer do not.
Eucharistic Prayer IV is based on the Anaphora of St. Basil used in the Eastern Churches. I probably do not pray this one enough.
There are Eucharistic Prayers for Reconciliation. I use these on Sundays in Lent, or when the scriptures or my homily suggest their use. As I read it:
Reconciliation I is a bit more focused on our reconciliation with God.
Reconciliation II
speaks more of our reconciliation with each other.
Of course, both aspects are present in the prayer as they are always present in true reconciliation, especially in the sacrament of Reconciliation.
There are four forms of the Eucharistic Prayer for use in Masses for Various Needs:
I The Church on the Way to Unity
II God Guides the Church on the Way of Salvation
III Jesus - Way to the Father
IV Jesus - the Compassion of God.
My read is, that these are intended for use at Masses for particular needs, the prayers for which are in the Roman Missal. I have only on a couple occasion, but to be honest, they were approved for use around the time I was ordained, so I never had much experience with them.
There are also Eucharistic Prayers for Masses where the vast majority of the assembly are children. These would be used at a school Mass and not on a weekend or Holy Day.