The answer
The three early Church Councils [Nicaea, Constantinople, Ephesus] are examples of the necessity for the anathema of heretics. Since then, certainly there have been some dire circumstances that necessitated anathema. The Church takes the threat of heresy very, very seriously, and first tries to council the heretic, but refusal to repent leaves the Church no option but anathema.Answered by His Eminence Metropolitan Youssef (opens in a new tab)