There have been five major heresies that have arisen within the history of the church. This explanation of each major heresy is very important knowledge for every believer, mainly because you will see hints of these within our modern culture, and unfortunately, within the church at large. The five heresies are:

Legalism
Gnosticism
Arianism
Pelagianism
Socinianism

Check out this PDF paper on the History of Heresy (Highly Recommended):

THE HISTORY OF HERESY – Five Errors that Refuse to Die – Phil Johnson (PDF)