Literal:

There is no historical record of the Nicolaitans from the first century.  The word itself means to “conquer the people”.  But apparently, there were some present in the church at Ephesus, where they were not tolerated.

Yet this you have, you hate the works of the Nicolaitans, which I also hate. Rev. 2:6

They were also present at Pergamum where they were tolerated.

So you also have some who hold the teaching of the Nicolaitans.  Rev 2:15.  

Most scholars feel that they were antinomians (opposed to moral law) or as the dispensationalist teaches it, “The Law has Passed Away.”  The antinomians teach that the dispensation of the gospel releases man from any obligation to keep the law of God.

What we do know comes from :

Irenaeus, ( in Irenaeus Against Heresies Book 2, Chapter 11)

Clement of Alexandria, (Stomata Book 2. Chapter 20)

Tertullian, (On Marcion)

They all wrote of their indulgences in vice, adultery, eating of things offered to idols, and of their love of carnal pleasure.  In direct opposition to what Paul wrote.

What shall we say then? Are we to continue in sin that grace may abound?  By no means! How can we who died to sin still live in it? Rom. 6:1 -2

This is plain and simple Lawlessness [2Th. 2:1-12].  They abused Christian liberty under the guise of adherence to the doctrine of grace.  Most of the book of Romans is devoted to refuting this lie, [c.f. Rm. 3:8; 6:15-31.]  Salvation means deliverance from the power of sin and death, not a continued life of sin and disobedience to the law of God.  For the Law has not passed away as the dispensationalist teaches.

Do we then overthrow the law by this faith? By no means! On the contrary, we uphold the law. Rom. 3:31

Symbolic:

During the early centuries of the church, many heresies appeared, among these Aryanism, Pelagianism, Donatism, and Nestorianism.

Aryanism: a view held by followers of Arius, a Christian priest who lived and taught in Alexandria, Egypt, in the early 4th century. Arius taught that God the Father and the Son were not co-eternal.  He saw the pre-incarnate Messiah or “the angel of the LORD” in the Old Testament as a divine being but rather a created being.  The consequence of this is that it makes Messiah an inferior being to the Father, and further that there was a point in time before which the Son did not exist.  This makes the Messiah a creature rather than The Creator.

Pelagianism: is a theological theory named after Pelagius (AD 354 – AD 420/440). He taught that there was no original sin.  That humans are capable of choosing good or evil.  Adam only set a bad example, but his actions were not imputed to his descendants.  Messiah’s atonement was only to set a good example for humanity.  Sinners are not victims, they are criminals. Babies are born innocent.

Donatism: This heresy arose during the Great Tribulation under Emperor Diocletian from 303-313 AD.  It is named for the Berber (present-day Tunisia and Algeria) Christian bishop Donatus Magnus.  He taught that the effectiveness of baptism and the Eucharist depends on the moral character of the minister.  In other words, if a minister who was involved in a serious enough sin were to baptize a person, that baptism would be considered invalid.

Nestorianism: This doctrine came from Nestorius, Patriarch of Constantinople who lived from 428–431 AD. He taught that the Messiah is two distinct persons, one human and the other divine.  This causes a problem with the atonement of the cross.  Which person died on the cross?  If only the human died, then atonement did not happen.  If the person who died was a deity?  How can a deity die?