The Nicene creed is a statement of faith of the early Catholic Church ratified by the Ecumenical Council of Nicaea in 325 AD in opposition to certain heresies, especially Arianism. These heresies, which disturbed the church during the fourth century, concerned the doctrine of the trinity and of the person of Christ.
This creed serves as the bar of orthodox Christian belief - to confess to parts of the creed without confessing to the entirety of the creed is to confess to being in heresy.
Here's the Latin and English versions of the creed. As I am more familiar with the Latin (as I chant to this every Sunday), I'll place the Latin first followed by the English transliteration.
Credo in unum Deum, Patrem omnipotentem, factorem caeli et terrae, visibilium omnium et invisibilium.
I believe in one God, the Father Almighty, Maker of heaven and earth, and of all things visible and invisible.
Et in unum Dominum, Jesum Christum, Filium Dei unigenitum, et ex Patre natum, ante omnia saecula. Deum de Deo, lumen de lumine, Deum Verum de Deo Vero. Genitum non factum, consubstantialem Patri, per quem omnia facta sunt.
And in one Lord Jesus Christ, the only-begotten Son of God, begotten of the Father before all worlds; God of God, Light of Light, very God of very God; begotten, not made, being of one substance with the Father, by whom all things were made.
Qui propter nos homines, et propter nostram salutem, descendit de caelis. Et incarnatus est de Spiritu Sancto ex Maria virgine, et homo factus est. Crucifixus etiam pro nobis, sub Pontio Pilato, passus et sepultus est. Et resurrexit tertia die, secundum Scripturas. Et ascendit in caelum, sedet ad dexteram Patris. Et iterum venturus est cum gloria, judicare vivos et mortuos, cujus regni non erit finis.
Who, for us men for our salvation, came down from heaven, and was incarnate by the Holy Spirit of the virgin Mary, and was made man; and was crucified also for us under Pontius Pilate; He suffered and was buried; and the third day He rose again, according to the Scriptures; and ascended into heaven, and sits on the right hand of the Father; and He shall come again, with glory, to judge the quick and the dead; whose kingdom shall have no end.
Et in Spiritum Sanctum, Dominum et Vivificantem, qui ex Patre Filioque procedit. Qui cum Patre et Filio simul adoratur, et conglorificatur, qui locutus est per Prophetas.
And I believe in the Holy Ghost, the Lord and Giver of Life; who proceeds from the Father and the Son; who with the Father and the Son together is worshiped and glorified; who spoke by the prophets.
Et Unam, Sanctam, Catholicam, et Apostolicam Ecclesiam. Confiteor unum baptisma in remissionem peccatorum. Et expecto resurrectionem mortuorum, et vitam venturi saeculi+.
And I believe in One, Holy, Catholic and Apostolic Church. I confess in one baptism for the remission of sins; and I look for the resurrection of the dead, and the life of the world to come.