The Catechism of the Catholic Church teaches that sacraments are "efficacious signs of grace, instituted by Christ and entrusted to the Church, by which divine life is dispensed to us. The visible rites by which the sacraments are celebrated signify and make present the graces proper to each sacrament. They bear fruit in those who receive them with the required dispositions" (1131) The Book of Common Prayer (Episcopal) defines a sacrament as a visible and outward sign of an inward and spiritual grace (857). A priest once told me that a sacrament is when something changes in both heaven and on earth because a priest or bishop invokes the Holy Spirit.

Protestants hold to two dominical sacraments, that is, sacraments commanded by Jesus. In particular, those are Baptism and Eucharist. Catholics, however, hold to an additional 5 sacraments, confession or reconciliation, confirmation, ordination, and holy matrimony.

Sacraments are celebrated by priests. In rare cases, lay people may celebrate. I thought this chart on wikipedia was helpful. http://en.wikipedia.org/wiki/Sacraments_of_the_Catholic_Church#Ordinary_and_extraordinary_ministers_of_the_sacraments

My artifacts are links to some sacramentaries.

First, there is the 1962 Missal. Unfortunately, it is in Latin which makes it far from useful for many of us. But it is a fun thing to look at, since this is how much of Christendom prayed for about 500 years. http://www.sanctamissa.org/en/resources/books-1962/missale-romanum-1962.pdf

More useful to us, here is the 1970 Missal. I could not find a full missal online, which seemed odd, but this gives us the Mass, Marriage, and Baptism. http://www.catholicliturgy.com/index.cfm/FuseAction/TextSubCategories/Index/4/SubIndex/67

Another source that may be useful is The Episcopal Church's 1979 Book of Common Prayer. The sacraments can be found in Table of Contents on their own or under "Pastoral Offices" and "Episcopal Services." http://www.bcponline.org/

Written between 1147 and 1150, these four books are what made Lombard famous. They are a long series of questions and answers in which Lombard addresses just about everything that the teachings of theology could address. More importantly, it is a systematic theology. An important aspect of this work is the numerous sources it cites, particularly from the various Latin Church Fathers. Many questions are left open-ended. Many commentaries on the Sentences, notably by Thomas Aquinas, carry on the discussion.

Book 1--The trinity
Book 2--Creation, both spiritual and physical things
Book 3--Incarnation
Book 4--Sacraments

The artifact I found is a partial translation. The authors have completed Book 1 and part of Book 2. Scroll part way down the page and you can find links to those. Additionally, you can find links to many commentaries on the Sentences at this website. http://www.franciscan-archive.org/lombardus/

Sources:
Catholic Encyclopedia: http://www.newadvent.org/cathen/11768d.htm
Internet Encyclopedia of Philosophy: http://www.iep.utm.edu/lombard/

This text was supposedly a decree of Constantine that gave the church great temporal authority. As a result of curing Constantine of leprosy, Pope Sylvester is given tremendous power over the western empire. It may have been created in the mid-8th century and used by Pope Stephen II in negotiations with Pepin the Short, who gave the Pope the Papal States in return for his support. Pope Leo IX argued that it was legitimate in 1054. Suspicions about its authenticity arose, and in 1440, Lorenzo Valla argued conclusively that it was written much later than the 4th century. The reformers, especially Luther, latched onto Valla's arguments.

I chose this ID because it intrigues me. Did the popes know that it was a forgery? Did someone forge it and put it in the right place to be found? How malicious was its creation? I wish we knew more about its origin.

As an artifact, I offer these lines from Dante's Inferno, Canto 19, in which Dante attacks the wealth and corruption of the popes and lays the blame squarely at feet of the Donation of Constantine (here just called "Constantine").

I do not know if I were here too bold,
That him I answered only in this metre:
"I pray thee tell me now how great a treasure

Our Lord demanded of Saint Peter first,
Before he put the keys into his keeping?
Truly he nothing asked but 'Follow me.'

Nor Peter nor the rest asked of Matthias
Silver or gold, when he by lot was chosen
Unto the place the guilty soul had lost.

Therefore stay here, for thou art justly punished,
And keep safe guard o'er the ill-gotten money,
Which caused thee to be valiant against Charles.

And were it not that still forbids it me
The reverence for the keys superlative
Thou hadst in keeping in the gladsome life,

I would make use of words more grievous still;
Because your avarice afflicts the world,
Trampling the good and lifting the depraved.

The Evangelist you Pastors had in mind,
When she who sitteth upon many waters
To fornicate with kings by him was seen;

The same who with the seven heads was born,
And power and strength from the ten horns received,
So long as virtue to her spouse was pleasing.

Ye have made yourselves a god of gold and silver;
And from the idolater how differ ye,
Save that he one, and ye a hundred worship?

Ah, Constantine! of how much ill was mother,
Not thy conversion, but that marriage dower
Which the first wealthy Father took from thee!"

Sources:
http://en.wikipedia.org/wiki/Donation_of_Constantine
http://en.wikipedia.org/wiki/Lorenzo_Valla
http://danteworlds.laits.utexas.edu/circle8a.html#donation