When and by whom were the problems of the early church dealt with

The main problem that the Church has had to deal with since the very beginning has been sin and Satan. Some of the other problems that the Church has had to deal with have been pride and ignorance. All throughout the New Testament, starting with Acts of the Apostles, and going through the various letters, are detailed the problems the early Church had to deal with. Some of these problems became so overwhelming they became heresies, like the Circumcisers in the first century which are dealt with in Acts, and Romans. Early Christians who thought that they still had to follow the Jewish law, not realizing that it has been fulfilled in Christ. This heresy has actually become its mirror opposite and the modern Protestants and Evangelicals now maintain that Christians have to follow NO laws, not realizing the St. Paul was talking about the Jewish law.
Other problems that the Church had to deal with early on were Gnosticism and Montanism